Beans and bacteria – a complex story of communication

Posted on by andy.winfield
The symbiotic relationship between legumes and soil bacteria has been known for well over a century. The intimate details of this relationship, however, are only recently being revealed. It is a very active area of research as understanding this symbiotic relationship could lead to strategies that help reduce the environmental impacts of food production. 
Rhizobia nodules on the roots of cowpea
(Vigna unguiculata). By Stdout
[GFDL (http://www.gnu.org/copyleft/fdl.html),
via Wikimedia Commons.
Special soil bacteria – known as rhizobia – reside within the nodules of legumes, such as peas, lentils, beans, alfalfa and clover, which are found along the roots of these plants. The bacteria take nitrogen from the air and convert it into ammonia, which the plant is able to use – a process known as nitrogen “fixing”.
This allows legumes to grow well in nitrogen-poor soils. This nitrogen is taken up in the plant material, which can then be worked back into the soil as a natural fertiliser for subsequent crops.
While this all might sound very straight forward – there are details about this relationship that remain unclear. How do the bacteria get into the nodules? Are there signals that the plant uses to stimulate the bacteria to produce nitrogen?

An answer to a century-old debate

In 2011, researchers from the John Innes Centre in Norwich answered the mystery of how nitrogen-fixing bacteria crossed the cell walls into the nodules of legumes. 
It had been a century-old debate as to whether bacteria produced the enzymes to break down the cell walls or whether the plant did. The researchers showed that it was the plant which supplied the enzymes to break down its cell walls in order to give the bacteria access.

How legumes communicate with their symbiotic bacteria

In 2010, Stanfordresearchers discovered the gene in plants that triggered the chemical signal required for the bacteria to fix nitrogen. They found that the rhizobia bacteria would just sit around in the legume nodules if the plant failed to produce the protein that’s required to spur the bacteria into nitrogen fixing mode. This was only part of the communication story.
It is energetically costly for the plant to produce and maintain the root nodules in which the bacteria live; usually the benefit of having a supply of nitrogen outweighs this cost. If there is sufficient useable nitrogen in the soil, however, the plant is able to reduce the number of nodules on its roots.
Communication between the shoots of the plant and the roots of the plant help regulate the number of nodules. The leaves transmit a signal to the roots to either develop more or get rid of rood nodules, depending on circumstances. The roots communicate back up to the leaves using molecules known as peptides.
Research published recently has now discovered that the plant shoots use plant hormones, known as cytokinins, which travel down the phloem into the roots to help regulate nodule development.

The environmental benefits of understanding legumes

Understanding the symbiotic relationship between legumes and soil bacteria is not simply a matter of scientific curiosity. The ability for legumes to produce natural nitrogen fertilisers is a trait that US researchers would like to potentially transfer to non-legume crops as a way of reducing the environmental impact of agriculture.
Manufacturing nitrogen fertilisers for non-legumes is extremely resource intensive. It has been estimated that to produce 68 kg (150 lbs) of nitrogen fertiliser – enough for one acre of corn – would be the equivalent of driving a car 1,046 km (650 miles).
Beyond that, nitrogen fertilisers release the powerful greenhouse gas, nitrous oxide, after they’ve been applied. Excess fertilisers also runoff agricultural land into rivers and lakes and eventually out into the ocean. This influx of nitrogen can provoke algal blooms and create oxygen deplete dead zones.

Therefore, there is great incentive to fully understand this relationship legumes have with soil bacteria. The environmental impact of agriculture could be significantly reduced by utilising legumes with their natural nitrogen fertiliser more by using them in more marginal land and using traditional breeding programs to select for drought resistance or temperature tolerance. In some countries, genetic engineering might even be used to introduce nitrogen-fixing abilities into non-legume species. Genetic modification, however, can be an inflammatory issue with considerable debate as to its pros and cons, particularly with respect to its use in food products.

Fruit: the good, the bad and the ugly

Posted on by andy.winfield

By Helen Roberts



Autumn is my favourite season. I love the colours, cooling temperatures and crispness of the air in the morning. One of the things I like most, however, is harvesting autumn fruit to use in cooking, baking and jams. So far, this autumn I have picked bucketfuls of blackberries, autumn raspberries, damsons, plums, apples, pears, quince, crabapples, rosehips and sloes.
It has been a wonderful harvest and my cupboards, freezer and larder are full of these delicious fruits as cakes, jams, jellies, butters or just shoved in the freezer to be used in the depths of winter. These are all fairly common and useful autumn fruits to most of us in the UK, but as I was poking about in my garden the other day I noticed quite an unusual fruit growing.
The fruit of chocolate vine (Akebia quinata).
Photo credit: Helen Roberts.
The fruit belongs to Akebia quinata,commonly known as chocolate vine – a vigorous climber that is growing really well in my garden. I have two plants growing up a north facing wall and a west-facing wall respectively and they are more or less planted in what I can only describe as gravel. They have always been strong growers despite neglect, but they have never produced fruit.
Last winter I decided to prune it back really hard with some hand shears as it was getting unruly. I thought I may have been too severe and they may not make it, but this summer they produced a mass of flowers and early autumn produced some lovely large weird sausage shaped fruit.
The plant is native to Japan, China and Korea. The sweet but insipid fruit pulp can be eaten, while the rind of the fruit is used like a vegetable in cooking – often stuffed with minced meat and deep fried. The leaves are used as a tea infusion.
Inspired by the weird and wonderful fruit in my garden, I ventured to the Botanic Gardens for a tour with botanical horticulturist, Andy Winfield. I told Andy I wanted to see some unusual fruit and seeds.

The Garden’s weird and wonderful fruit

The first plants on the tour, which were listed at the welcome hut of current things to see, were sunflowers. The variety, ‘Giant’, produced a rather wonderful forest that rose a couple of metres above us. My sons have grown this variety but the ones in the Garden are colossal by comparison.
Cape gooseberry (Physalis peruviana) fruit is wrapped in
a papery calyx. Photo credit: Helen Roberts.
In the same bed were two species of Physalis, a genus in the nightshade family (Solanaceae). Physalis philadelphica, or the tomatillo, bears small green-purple fruit and are a staple of Mexican cuisine in dishes such as salsa verde. I tried one and it tasted a bit like a very sweet tomato – I wasn’t enamoured, but I think they are better cooked. Physalis peruviana, the Cape gooseberry, on the other hand has a wonderful sweet pineapple-like flavour. The fruit is smaller than the tomatillo, bright orange in colour, with lots of little seeds inside. Just like the tomatillo, the fruit is enclosed in an inflated papery calyx.
Sweet chestnut (Castanea sativa).
Photo credit: Helen Roberts.
Walking towards the hops in the western herb garden we walked past a fairly young Sweet Chestnut tree (Castanea sativa), which had dropped numerous spiky chestnuts, many of which had split to reveal the lovely glossy brown nuts inside. These nuts are roasted in many different countries and used to make stuffings for meat or vegetables. I have a bit of a sweet tooth so I am very fond of the use of these nuts in confections, puddings, desserts and cakes, my favourites being crème de marron and marrons glacés. Chestnuts used to be the food of the poor and were used by peasants as a staple instead of grains in parts of southwest France and parts of Italy. In France the chestnut tree is often referred to as l’arbre à pain, or the ‘bread tree’ as the chestnuts were ground into flour. The trees can grow to an impressive 20-35 metres in height with a 2 metre diameter trunk.

The cocoa tree’s tiny flowers are clustered
directly on the trunk. Photo credit: Helen Roberts.
My tour continued into the glasshouses to look at some economically important plants as well as others that are simply weird and wonderful looking. The cocoa tree, Theobroma cacao, was our first stop – after all, who could pass on chocolate? This smallish tree with large glossy green leaves lives in the Garden’s tropical glasshouse and is a native of central and South America. At first glance it’s quite unassuming, but look a bit closer and you can see the distinctive shape of the cocoa pod. I was amazed by the size of the tiny cream flowers that grow in clusters directly on the trunk – a term known as cauliflory – and that these tiny flowers can produce such a large fruit. The pod contains 20-60 seeds within a white pulp, which are the main ingredient of chocolate.
The history of cacao dates back to the early formative period (1900-900 BC) when it was considered a very important part of Mesoamerican culture. The beans constituted both a ritual beverage and a major currency system in pre-Columbian Mesoamerican civilisations.
“We had a volunteer working at the gardens who used to work for J S Fry & Sons – a chocolate manufacturer in Bristol,” revealed Andy. “He said you can make about five bars of chocolate from one pod!”

The citrus known as Buddha’s hand (Citrus medica var. digitata).
Photo credit: Helen Roberts.
The tropical glasshouse also houses a weird looking citrus called ‘Buddha’s Hand’, Citrus medica var. digitata, which is cultivated in Japan and China. It looks like a small wizened citron with fingers. The fleshy peel can be steamed and candied fresh or it can be used for its highly aromatic and fragrant zest. The fruit has been an offering in Buddhist temples for a long time.
After the glasshouses, Andy took me to the pond where there is a rather ancient looking medlar (Mespilus germanica) tree, laden with fruit. I see this tree a lot in the various gardens I visit, but I have never used the fruit for anything.
 

Fruits of the medlar tree (mespilus germanica).
Photo credit: Helen Roberts.

“The fruit needs to be ‘bletted’,” said Andy, “which is when the fruit is browned by rot after a frost or naturally in storage over time. Then it can be eaten raw or used to make desserts, jelly, medlar cheese [akin to lemon curd] and wine.”
I recall my mother making medlar jelly, but I cannot remember ever tasting it. Perhaps I will try making something of the medlars after our first frost. My tour inspired thoughts of jam making sessions with some new and exotic fruits. There are lots of weird and wonderful fruits at the Botanic Garden right now – definitely worth a visit – who knows how it will inspire you?!

Raising the ‘green’ roof

Posted on by andy.winfield

By Helen Roberts


We currently have a real shortage of housing in the UK and the estate agency Savills has estimated that there will be a shortfall of 160,000 homes in the next five years unless local authorities act. With this in mind, I started thinking of the building industry and how sustain­­able building design has become increasingly important over the last few decades. Not only does the industry consider the sustainability of the materials themselves, but designs aim to reduce consumption of non-renewable resources and minimize waste during and after the life of the building, while creating a healthy and comfortable environment for the occupants.

Within the field of sustainable building design is the subject of green roofs. This is an area of design that holds great interest to me, as I am a landscape architect with previous training in plant sciences. Green roofs play a pivotal role in urban environments by reducing rainwater runoff, reducing energy consumption for heating and cooling, heat island mitigation, creating valuable wildlife habitats and also making an aesthetically pleasant landscape for people to escape from the urban environment. 

What is a green roof?

Green roof on Chicago City Hall. Photo credit: TonyTheTiger
[CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)
via Wikimedia Commons

A green roof is a platform or roof on which vegetation is grown or wildlife habitats are created. The basic elements include a waterproofing membrane covered with a growing medium and vegetation. The design, ecology and aesthetics of a green roof can vary considerably, however, and can be adapted specifically to suit a particular location or design brief. Plants in containers on a roof top are not considered to be a true green roof.
The term green roof, however, can also be used to describe roofs that incorporate green technology, such as solar thermal collectors or photovoltaic (solar) panels.

The history of green roofs

Green roofs are not a new concept. Dwellings of the Neolithic period, such as the Neolithic village of Skara Brae in Orkney, are thought to have had turf roofs. The Hanging Gardens of Babylon, one of the wonders of the Ancient World, were extravagant green roof gardens, thought to be irrigated by about 35,000 litres of water brought in through aqueducts and canals.

The houses at Skara Brae, Orkney were thought to have
had turf roofs. Photo credit: Antony Slegg
[CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)],
via Wikimedia Commons

Turf or sod roofs were common centuries ago in Scandinavia and can still be seen in places like the Faroe Islands. I visited Lund, Sweden recently and saw beautiful turf roofed farmhouses in the museum of cultural history. The turf helped keep dwellings cool in the summer and warm in the winter. However, these structures would most likely have leaked and also would have had the inconvenience of burrowing wildlife!
Modern green roofs didn’t develop until the 1970s in Germany, when legislation was passed to encourage the introduction of green roofs. Unlike the historical turf roofs, modern green roof designs include drainage and root protection measures, as well as lightweight growing media.
The UK is somewhat behind continental Europe in terms of using government policy to implement green roof technology. But things are changing and there has been an increase in the use of green roof technology over the past decade. In fact, Bristol’s development policy (Bristol Development Framework Core Strategy; adopted in June 2011) encourages the incorporation of green roofs as a way of enhancing the biodiversity value of new building developments and views green roofs as an essential asset of the strategic green infrastructure network.Bristol  

Green roofs can be extensive, intensive or semi-intensive

Green roofs vary in ‘intensity’ in terms of the depth of substrate used and the level of maintenance needed, which affects the type of vegetation that can then be grown. A typical green roof will have, on top of the roof itself, a layer of waterproofing, a root barrier, protection/moisture retention matting, a drainage layer, a filter sheet, the growing substrate and then the plants. Green technology, such as solar panels, may also be incorporated into the design of the vegetated roof.
Green roofs are classified as extensive, intensive or semi-intensive in nature. Extensive green roofs are less than 100 mm deep and are relatively low maintenance. Their shallow depth means they are lighter but that they can support fewer vegetation types. This means they generally have lower biodiversity value and limited water holding capacity. Most people will be familiar with sedum matting as a common form of extensive green roof.

Construction layers of a green roof.
Photo credit: thingermejig (flickr.com)
[CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)],
via Wikimedia Commons

Semi intensive green roofs have substrate depths of about 100 mm to 200 mm, require moderate maintenance, can support a greater range of plant species and have the ability for rainwater attenuation.
Intensive green roofs have deeper substrates (over 200 mm) and therefore require more substantial structural support. The deep substrate can sustain more elaborate plantings, including many different tree and shrub species, which offers a more garden-like space for users. Intensive green roofs require more maintenance and complex drainage and irrigation systems, but can offer rainwater attenuation and a greater degree of species biodiversity.
The aim of the green roof will ultimately influence its design. If, for example, the aim is simply to have an insulating effect on the building, a low-maintenance extensive green roof with low-lying vegetation would probably be sufficient. If, however, the aim is to attract and enhance wildlife, an intensive design is likely required to support a diversity of plant species that can provide a variety of structure and microhabitats. I will discuss biodiversity and wildlife green roofs in more detail in my next blog post.


The benefits of green roofs:

Green roofs help improve the urban environment in many ways, from creating a natural space for office workers to enjoy to helping mitigate the urban heat island effect. Here are some of the benefits of green roofs:

Creating a biodiverse space and a relaxing place

Green roofs can increase biodiversity in urban areas where ground level space has been developed and valuable green corridors lost. Sky-high gardens can be important stepping stones for wildlife and can create habitat and forage for a variety of species, which wouldn’t exist with conventional roofs.
These places can also provide a haven for people to visit or to just view and offer a respite from a hard urban setting. 

Green roofs slow down runoff and help reduce flooding

There is a requirement now in the UK (under the Flood and Water Management Act 2010) that new developments mitigate storm water runoff and include appropriate water management systems. An established green roof can significantly reduce the peak flow rates and total volume of water runoff. Water is stored by the plants and substrate and is released back slowly into the atmosphere by evapotranspiration and evaporation. The plants also help filter out pollutants in the rainfall.
Many features of Sustainable Urban Drainage Systems (SUDS), such as permeable surfaces and swales, are not easily incorporated into a hard urban and so green roofs are considered a good solution to reducing storm water runoff. Interestingly, it has been found that in the summer 70-80% of rainfall can be retained in a green roof and in winter 10-35% (due to differences in evapotranspiration in summer and winter). 

The cool down effect of green roofs

Urban areas that are hotter than nearby rural areas are described as heat islands. The additional heat means more energy is used in summer for cooling (air conditioning and refrigeration), there are more incidents of heat-related illness and mortality and there are implications for air and water quality. Green roofs help improve local air quality and cool the urban environment by reflecting more of the sun’s rays compared with conventional roofs. The plants shade and insulate the underlying roof and have a cooling effect as water is released through evapotranspiration and evaporation – the building equivalent of sweating.

Green roofs reduce energy consumption

The thermal insulation properties of green roofs reduce the need for air conditioning in summer and heating in winter, decreasing associated emissions and dependence on non-renewable resources. 

Green roof allotments

There is increasing interest in the use of green roofs for food production and this ties in closely with the provision of amenity space. There is limited green space that can be used at ground level for food production in urban areas, so the logical step is to go up!. Roof-top allotments reduce food transportation and help increase the supply where the demand exists. For the individual household, it can help reduce food costs and provide many benefits associated with growing your own food. For a community, rooftop gardens can become a centre for social cohesion.
Though there are examples of agri-roofs, mainly in Asia, the use of roofs for food production is relatively unexplored and will provide ‘food for thought’ in the design of future green roofs.

Raise the roof on green roofs

With their many benefits, green roofs are likely to become a vital component of building designs in the future. New developments are imminent in the face of a housing shortage and green roofs offer an opportunity to improve the urban landscape, providing habitat for essential species, such as pollinators, and potentially helping respond to challenges with food security. Green space that is lost on the ground needs to be created up above with the transformation of featureless barren roofs into beautiful diverse green places. 

Children take a ‘walk through time’ at the Bristol Botanic Garden

Posted on by andy.winfield
It’s 1 pm, the sun is shining and the volunteer guides are starting to gather near the welcome lodge in anticipation of 60 Year 4 children arriving at the Botanic Garden for a tour. It’s my son’s school, Horfield CEVC Primary School, and so I’ve decided to come along for the tour and get a glimpse into how the Garden is viewed through the eyes of eight and nine year olds.
Anne is one of the volunteer guides at the garden and she and I get chatting while we await the children’s arrival. She was a teacher for 40 years – teaching at GCSE and A levels. She laughs as she tells me she was a bit nervous she would find touring younger children challenging when she started giving these school tours at the Garden. She soon found, however, that though it was different from teaching upper level students, it was also just good fun.
Volunteer guide Tony gives a talk to Year 4 students
from Horfield CEVC Primary School prior to their tour.
“I’m not responsible for making sure they learn the curriculum, I’m here to entertain them with interesting stories about the plants we have here in the garden – to get them excited and inspired by what they see,” Anne says from a shady bench.
The guides have come prepared; they know the Horfield children have been learning about Egypt and different habitat types. As well as discussing the logistics of touring sixty children around the garden in small groups, they check in with each other about plants that might be important to point out that will link to the topics and themes they’ve been learning in the classroom.
Then the coach arrives.

A tour through the glasshouses

Before the children break into small groups to go around the garden, volunteer guide Tony gives a very brief talk about what plants need to survive. The children enthusiastically put up their hands in response to Tony’s question of what plants need to grow. Horfield Primary is lucky enough to have a garden and most of the children will have grown plants in the classroom at some stage (my son brought a runner bean home from school a few weeks back that’s doing splendidly). So, although photosynthesis hasn’t been taught by Year 4, there are other opportunities where the children are learning the basic needs and processes of plant growth.
Students have a look in the pitcher plants in the sub-tropical
zone of the glasshouses.
Baking sun and a tight schedule keeps the introductory talk brief and I follow Anne’s small group down into the glasshouses. She points out the Deadly Nightshade along the way and talks about the large black poisonous berries – a good wow factor for the kids right off the start!
In the sub-tropical zone, the children talk about the challenges of plants growing in a rainforest beneath a heavily shaded canopy and some of the adaptations they’ve made to get alternate sources of food. They have a look into the pitcher plants to see whether any wayward insects have fallen into the plant’s pitcher-shaped trap. As Anne walks by the lichen, she talks about how lightning changes the nitrogen in the air into a form that’s easier for plants to use – lichens need a continual supply of nitrogen to survive. Lightning helps feed plants? This has the children’s attention.
Having a look at the giant lily pads in the pond in the
tropical zone of the glasshouses.
In the tropical zone the giant lily pads (Victoria) impress the children immediately. Then Anne points out the papyrus that’s growing at the corner of the pond and the children quickly make the link between this plant and the papyrus paper that they’ve been learning about in their Egyptian studies. As I switch between the different groups I hear one of the other guides tell a story from Egyptian Mythology about how the Scorpion-godess, Selkis, protects the child Horus by hiding him in a papyrus thicket.
The lotus plants (Nelumbo nucifera) are also linked to Egypt as there is a Nymphaea lotus that grows in the Nile. Anne encourages the children to splash some of the pond water onto the leaves of the lotus plant and I watch as two girls are astonished at how the leaves repel the water.
Water beads off the leaf of the lotus plant.
Some of the other highlights in the tropical zone were the cocoa plant, vanilla and cotton. The Madagascar periwinkle (Catharanthus) is also pointed out for its utility in treating leukaemia.
As the children stand beside the cacti in the glasshouses, they are told that some of these plants will go 10 years without ever experiencing rainfall – longer than these children have been alive. Anne and the other guides talk about all the adaptations these plants have made to go for long periods without water.
Students are given an opportunity to experience what
happens to Mimosa plants when you touch their leaves.

Time travel through the evolutionary dell

I leave the heat of the glasshouses to join Tony’s group as they begin their walk through the evolutionary dell. Tony is telling the children about horsetails (no friend of the gardener) and pointing out the nodes of the plants. He tells them that 350 million years ago this little snippet of a plant would have been the size of a tree! The kids crane their necks up imagining and as we walk toward the tree ferns one of the girls says “It feels like time travelling!”
Tony takes the children on a walk through time in
the evolutionary dell.
Indeed it is like time travelling in the dell. In the 100 m span of the dell, we travel 200 million years from the horsetails (350 mya) to the first flowering plants (150 mya), such as the magnolia that’s on the left as you leave the dell. Surrounded by ferns, moss, horsetails, Wollemia and other conifers, the guides tell the children about how plants reproduced before the evolution of flowers and pollinators.

It’s never long enough

Somehow an hour seemed to fly by and before long the guides were rushing through the last few displays before sending the children off on their coach. As I had the opportunity to hop between the different groups I got the great sense that each group would have left the garden with a different experience as each guide has their own style and favourite stories associated with the garden. It’s never possible to see everything, but hopefully that means some of the children will encourage their parents and guardians to bring them back for another visit!
Tony holds up a horsetail and talks about plant nodes.

Linking to the curriculum

Mrs Amy Parkin, one of the Year 4 teachers at Horfield Primary, was kind enough to speak with me the next day after the tour about how tours such as this link with the classroom curriculum. This is the first time Horfield Primary has done the tour at the Botanic Garden and it was prompted by Curator Nick Wray giving a talk earlier this year to the Key Stage 2 children.
“We had two weeks where we talked about prehistoric Bristol, dinosaurs and fossils,” said Mrs Parkin. “Each class did a science trail with various outside activities and we also had speakers come in to talk to the children. Nick spoke about what plants would have been around 160 million years ago and he brought in some different species to show the children.”
As well as learning about Egypt, the Year 4 children have also covered the topic of habitats under their science curriculum and there are also cross-curricular links with their geography topic of water.
“The tour at the Botanic Garden helped extend the children’s knowledge on habitats,” said Mrs Parkin. “We focused on animals in different habitats in the classroom and in the tour we saw how plants adapt to different habitats as well.”
This tour will also give the Year 4 students a taste of what lies ahead as they will have plants as a topic in Year 5.

Talking with the students after the tour

After the tour I had a chance to speak with Megan and Henry about what they thought of the Botanic Garden. Megan said “I really liked the giant lily pads, especially since a small child could sit on one!”, while Henry really liked the giant lemon that was in the glasshouse.
When I asked Megan and Henry what the most interesting thing they learned was, Megan said she couldn’t believe that some plants can live for 10 years without water. Henry, on the other hand, learned something new about pollination, “There are lots of different bugs that pollinate plants – blowflies and beetles – and birds too!”
The Botanic Garden will run about 15 school tours during the months of June and July, with the help of their dedicated volunteer guides. These tours are in keeping with the Garden’s mission to promote education and awareness as well as to encourage and foster interest in plants within the Bristol community. In fact, the garden would like to run more school tours, so if you are involved with a local school and are interested in a trip to the Botanic Garden, please contact them via:   www.bristol.ac.uk/botanic-garden

The strawberry timebomb: how basic plant biology can help you store your produce

Posted on by andy.winfield
Two days ago I purchased an alarmingly large number of strawberries. I couldn’t help myself. Grown in Cheddar, these sweet little ripe morsels are a welcome break from the onslaught of last year’s apples and a plethora of citrus. When you try to eat seasonally and with reduced transportation miles, you appreciate the appearance of new season fruit that much more.
Non-climacteric fruit, such as strawberries, do not continue to ripen once picked
Strawberries have to be picked at their peak of ripeness as
they don’t ripen any further once they’re separated from the
plant – known as non-climacteric fruit.
Photo credit: Nicola Temple

The moment I placed the box on my kitchen counter, however, I felt as though a timer began counting down on a bomb. But rather than finishing off with an explosion, it would be more of a moldy, decayed mess of fruit wasting away. In response, I did as my mother before me did, and I issued relentless alarm calls to my family, “Eat strawberries…strawberries would go well with that…why are you eating that pear? EAT strawberries!” Luckily the troops rallied and I’m happy to report that there was no waste.

This strawberry time bomb is more technically that stage between when a fruit has reached its peak ripeness and when it first starts to deteriorate. Strawberries, unlike some other fruits, do not continue to ripen when picked and so they have to be picked when they are perfectly ripe otherwise they will taste somewhat inferior. The rotting timer starts the minute the strawberry is picked and is running down from field (or poly tunnel) to consumer. So why is it that strawberries don’t ripen further after they’re picked, but fruits like tomatoes do?

Ethylene and rapid respiration: qualities of the climacteric fruit

The answer lies in some basic plant physiology. Some fruits produce a lot of ethylene and undergo rapid respiration during ripening, which means the fruits continue to ripen even once they are separated from the plant. These are known as climacteric fruits. As one would expect, non-climacteric fruits produce very little ethylene, do not undergo periods of rapid respiration and do not ripen any further once picked from the plant.
Ethylene plays a major role in the regulation of the ripening process and affects the rate at which the fruit ripens. Producers use this to their advantage. Bananas, for example, are picked hard and green and stored mature but unripe. When a retailer places an order, the bananas are placed in a room and ethylene is pumped in to ripen the fruit up for sale.
Ethylene is even used by industry as a de-greening agent for non-climacteric fruits, such as citrus. It is used to break down the green chlorophyll pigment in the peel of many citrus fruits, like orange and lemon, which essentially makes a somewhat unripe fruit appear ripe to the consumer.
The genetic regulation behind the climacteric characteristics of plants is very complex and not yet completely understood. For example, different melon varieties can be climacteric or non-climacteric. If a climacteric melon is crossed with a non-climacteric melon, the fruit is generally climacteric, suggesting it might be a genetically dominant character trait. Yet, other experiments that have crossed two non-climacteric melons have generated climacteric melons. This implies that the trait is more complex than a dominantly inherited trait.

Examples of climacteric versus non-climacteric fruits

There may be a few items on these lists that make you take a second look as we don’t commonly think of them as fruits, but rather as vegetables. However, aubergines, courgettes and cucumbers are indeed fruits.
Climacteric Fruits
Non-climacteric fruits
Apple
Aubergine
Apricot
Bell peppers
Avocado
Cherries
Banana
Citrus fruits
Cantaloupe
Courgettes
Fig
Cucumber
Kiwi
Grapes
Mango
Lychee
Passion fruit
Most berries
Peach
Pomegranate
Pear
Strawberries
Plum
Pineapples
Tomato
Watermelon

How to store climacteric fruits and non-climacteric fruits

Tomatoes are a climacteric fruit - they continue to ripen after picking.
Different varieties of tomatoes, a climacteric fruit, on
display at a French market. Photo credit: Shelby Temple.

Knowing the difference between your climacteric and non-climacteric fruits can help you store them appropriately.

Climacteric fruits are best stored at room temperature. They are picked before they are ripe and refrigeration can slow the ripening process. Since these fruits will continue to ripen after picking, they generally have a shorter shelf-life, but refrigerating them once they have fully ripened could extend the shelf life somewhat. 
Non-climacteric fruits, on the other hand, are picked when fully ripe and are best stored in the refrigerator to slow their deterioration. They generally have a longer shelf-life as they don’t continue to ripen (though I don’t consider this to be true of berries).
Don’t store climacteric fruits with non-climacteric fruits as the ethylene produced by fruits such as bananas can speed up the rotting process of an already ripe fruit. However, this natural ethylene production can also work to your advantage. Avocados, for example, are often sold hard as rocks and if you wish to speed up the ripening process, you can store them with bananas in a paper bag on the counter.

The climacteric character of fruit is an active area of research due to the direct applications for the way we pick, transport and store our food. As much as I am an advocate for scientific solutions, I hope overindulging on the sweet delicious fruit of local strawberries during this precious time of year is never resolved – it is simply a matter of tradition.

The science of nectar

Posted on by andy.winfield
Nectar is that sweet reward that flowering plants provide animals in exchange for their services as pollinators. It sounds incredibly simple on one level – much like rewarding a dog with a treat after it obeys a command. However, dig a little deeper and you realise that the reproductive success of the plant is dependent on very subtle yet complex characteristics of this substance – including when it’s produced and how much is produced, as well as its very composition.
Flowering plants will optimise the characteristics of their nectar in order to influence the foraging behaviours of pollinators and ultimately improve their reproductive fitness. The characteristics of the nectar not only determine which pollinators are attracted and when they come, but how frequently they visit and how long they stay. Suddenly one realises that there is an extremely complex system of regulatory mechanisms behind nectar secretion, which have not only influenced the evolution of flowering plants, but of the pollinators themselves.
Red admiral butterfly close up
Red Admiral butterfly (Vanessa atalanta) drinking nectar. 
Photo credit: Shelby Temple.

Nectar isn’t just about sugar

But before we get into the evolution, let’s first consider what nectar is, because as it turns out it’s not just about sugar – there are a number of things in nectar that are important for pollinators.
There is no denying, however, that carbohydrates – sugars such as glucose, sucrose and fructose – are usually the main constituent of nectar. Nectar will be anywhere between 7 to 70 % carbohydrates per water weight [1]. Other sugars might also be present in small amounts as well as sugar alcohols, such as sorbitol. It is these sugars that are the primary energy source for nectar consumers.
Amino acids and proteins are the next most abundant solute in nectar after the sugars. There are essential and non-essential amino acids, which are the building blocks for proteins and there are some non-protein amino acids that are constituents of enzymes and preservatives. It is thought that the amino acid and protein content of nectar may play a role in the taste preferences of insects [1], presumably related to their nutritional needs.
The water content of nectar may also be an important reward for pollinators, particularly in dry habitats.
Nectar also contains important ions, such as potassium, as well as antioxidants, trace amounts of lipids and some secondary compounds that seem to be associated with resistance to herbivory. 
Macro photography bee
A bee gathering its nectar reward in the Botanic Garden.
Photo credit: Shelby Temple.
Many species have also been shown to have antimicrobial compounds in their nectar, which prevents microbes from growing in the nectar as well as inhibiting florally transmitted diseases [2].
Terpinoids, which are the volatile organic compounds that give flowers their scent, also accumulate in the nectar.
The composition and consistency of nectar is extremely variable as it is tuned to the needs of the nectarivores (it’s a word…really). Flowers frequented by hummingbirds, for example, generally produce nectar in small amounts with high sugar content, while those frequented by more generalist passerine birds produce dilute nectar in large quantities. There has been some evidence that honeybees have a preference for warmer nectar that’s less viscous, regardless of the sugar concentration [3]. Bats also seem to prefer less viscous nectar, though will preferentially select more dilute nectar as the water content is extremely important for their rehydration.

Not all nectar is produced in the flower

Nectar is produced in glands known as nectaries. The glands are commonly found at the base of flowers, where they produce nectar as a reward for pollinators. However, there are also extrafloral nectaries located elsewhere on the plant, often on the leaves or petiole – the stalk that attaches the leaf blade to the stem. These nectaries provide a reward for mutualistic animals, almost exclusively ants, which benefit the plant. The ants help protect certain plant species by getting rid of the eggs of herbivorous insects deposited on the foliage and in return they feast on the nutrient rich nectar secreted by the extrafloral nectaries.
Extrafloral nectaries might be particularly critical at certain times in the plant’s lifecycle. For example, there are often nectaries located on the pedicelthat secrete nectar when the flowers are in bud. This attracts ants, which help protect the vulnerable flower buds from herbivorous insects and improves the reproductive success of the plant [4].
Unlike nectar produced in the flower, nectar produced in the extrafloral nectaries is far less variable as it is attracting mostly ants.

Darwin’s orchid: a classic example of the coevolution of flowering plants and their pollinators

Producing nectar may use up to 37% of a plant’s available energy [5]. This means that producing it comes with some cost to the plant, but these costs are clearly outweighed by the benefits of attracting pollinators that are far more efficient than relying on wind or water.
The evolution of flowering plants and their pollinators is the most frequently used example of coevolution – the physical characteristics of both flower and animal evolving to become more specialised. It was around 120 million years ago that honeybees developed longer tongues than their short-tongued ancestors in order to access the nectar reward flowers had started to produce. Their social structure became more complex and they became fuzzier and developed pollen baskets in order to carry protein-rich pollen, but also facilitating their role as pollinators.
Darwin’s orchid in bloom at the Botanic
Garden last year. Photo credit: Andy Winfield.
The flowers also changed shape in response to the preferences of their pollinators. The most classic of these examples is Darwin’s orchid (Angraecum sesquipedale) with a flower depth of 20 to 35 centimetres. The Madagascar orchid was named after Darwin because he proposed, based on its shape alone, that it had to be pollinated by an insect with a proboscis of lengths unheard of at the time. Forty years later, Morgan’s sphinx moth (Xanthopan morganii), was discovered with an unusually large proboscis…and it was indeed the pollinator of this orchid.
It is also thought that nectar chemistry itself has evolved in response to pollinators. As mentioned earlier, bats prefer nectar with low sugar concentrations and as a result bat pollinated plants from very diverse and distantly related taxonomic groups have evolved nectar with low sugar concentrations.

Deceit and robbing

Not all flowers use nectar – some have non-rewarding flowers. Around 30-40% of species within the orchid family do not produce rewarding nectar in their flowers [6] and instead use different methods to attract pollinators. Orchid flowers may look like another species that provides nectar or they may mimic shelters or brood-sites or even pollinators themselves in order to draw the attentions of individuals looking for a place to shelter or for a potential mate (such as in bumble-bee orchids).
Just as plants have found ways to get pollinated without producing nectar, some animals have found ways to get nectar yet avoid being pollinators. Some flower visitors – known as nectar robbers – will avoid the normal route to the nectar, usually avoiding the floral opening all together and pierce or bite the flower elsewhere to extract the nectar directly without coming into contact with any of the reproductive parts.
For many years it was thought that nectar robbers had a negative or neutral effect on the plants, but over the last couple of decades, research has shown they can also have a positive effect on the plant. Firstly, some nectar robbers do ultimately end up pollinating the plants. Secondly, their presence can modify the behaviours of the pollinators. For example, if flowers have less nectar (because the robbers have extracted some) then pollinators will visit more flowers, increase their foraging range, travel further distances and spend less time at each flower – all of which could improve cross pollination and increase genetic diversity. Maloof et al [7] provide a good review on this topic.  
There has been extensive research done on the characteristics of nectar and its relationship with pollinators. More recent research, however, is starting to unravel the mechanisms by which plants produce nectar – identifying some of the pathways sugars are transported within the plant and concentrated in their nectar [8]. There is still lots to learn.

Sources:

[1] Pacini E, Nicolson SW (2007). Chapter 1: Introduction, In: Nicolson SW, Nepi M, Pacini E (Eds.) Nectaries and Nectar. Springer: The Netherlands. ISBN: 978-1-4020-5936-0. (pages 8-10).
[2] Sasu MA, Wall KL, Stephenson AG (2010). Antimicrobial nectar inhibits a florally transmitted pathogen of a wild Cucurbita pepo (Cucurbitaceae). American Journal of Botany 97 (6): 1025-1030. (link)
[3] Nicolson SW, de Veer L, Köhler A, Pirk CWW. Honeybees prefer warmer nectar and less viscous nectar, regardless of sugar concentration (link).
[4] Bentley BL (1977). The protective function of ants visiting the extrafloral nectaries of Bixa orellana (Bixaceae). J. Ecol. 65 (1): 27.38.
[5] Pyke GH (1991). What does it cost a plant to produce floral nectar? Nature 350: 58-59. doi: 10.1038/350058a0
[6] Johnson SD, Hobbhahn N, Bytebier B (2013). Ancestral deceit and labile evolution of nectar production in the African orchid genus Disa. Biol. Lett. 9 (5): 20130500. doi: 10.1098/rsbl.2013.0500.
[8] Lin IW et al.(2014). Nectar secretion requires sucrose phosphate synthases and the sugar transporter SWEET9. Nature 508: 546-549. doi: 10.1038/nature13082

The Native Bluebell: Britain’s favourite flower in trouble

Posted on by andy.winfield

by Helen Roberts


It is a beautiful spring morning in May and I am taking my children for a walk. We are venturing to some local woods on the edge of the Mendip Hills, a stone’s throw away from our house.

The woods are secreted away in a limestone gorge. The stubby cliffs of limestone are clothed in ivy and gradually open up into a steep sided valley. A tiny stream channels through the gorge; tributaries often disappearing down sink holes. We trek across a ploughed field to the gate that lets us into the wood.

As we pass through the kissing gate, there is an overwhelming smell – it’s the heady perfume of the native bluebell, Hyacinthoides non-scripta. The woods are carpeted in vibrant blue (the colour almost glows it is so vivid), dotted with ferns and intermingled with wood anemones (Anemone nemorosa), Lady’s smock (Cardamine pratensis), wild garlic (Allium ursinum), greater stitchwort (Stellaria holostea) and yellow archangel (Lamiastrum galeobdolon). It is one of my favourite places for a walk in the spring and it is made special because of the sight and smell of bluebells.

Bluebell woods in Britain are under threat

British woodland with bluebells in bloom

Bluebells blanket the ground in British woodlands
this time of year. Photo credit: Shelby Temple

Bluebell woods are an iconic part of our natural heritage and are one of the most beautiful sights to encounter in the British countryside. They were voted Britain’s favourite flower in Plantlife’s ‘CountyFlowers’ project in 2002 and we have 50% of the entire world population in our country.
Sadly, the indigenous bluebell, Hyacinthoides non-scripta, is in danger because it cross breeds with the commonly planted Spanish bluebell (Hyacinthoideshispanica) and with the resulting fertile hybrid (Hyacinthoides x massartiana). Molecular studies have shown that the Spanish bluebell and the native bluebell have a shared ancestor [1], but Hyacinthoides non-scripta has developed in isolation over the last 8,000 years, its range to the north of the Spanish bluebell [2].

Polluting bluebell genetics

The Spanish bluebell has been grown as a garden plant in Britain since 1683 [3] and it and its hybrid have now ‘gone over the garden wall’ and are encroaching on our native bluebell woods. Its leap over the ‘wall’ has most likely been facilitated by bulbs being thrown out or dumped near native woodlands. The Spanish bluebell looks a thug of a plant next to our native one – being a much bigger plant – and is reported far more vigorous. 
Hyacinthoides non-scripta
Native bluebells are low to the ground and
deep blue to violet in colour. The flower spike
distinctly nods to one side. Photo credit: Glyn Baker
[CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)],
via Wikimedia Commons
In its native range, the Spanish bluebell has a wider ecological tolerance to that of the native bluebell. It copes better with drier and more exposed conditions and can therefore grow in more open sites, such as roadside verges and waste ground. The Spanish bluebell is a garden favourite because it’s so much larger and can establish itself and grow quickly. Both the Spanish bluebell and its hybrid, however, have the ability to take over leading to the loss of genetic integrity of the native bluebell.
The native and bluebell hybrid are really difficult to tell apart even by expert botanists and sometimes the only way to distinguish between them is to apply DNA analysis. Many gardeners are sold the hybrid mislabeled as ‘English Bluebell’ and have planted them in good faith thinking these were the native bluebell.

The hybrids were first recorded in the wild in 1963, though they were likely there long before then as the Spanish bluebell was first recorded in the wild in 1909. The Natural History Museum gives good guidance on how to identify your bluebells with a supporting video given by botanist Fred Rumsey here.

Nation-wide bluebell surveys show extent of Spanish bluebell invasion

A survey performed by Plantlife International in 2003 found that one in six broadleaved woodlands surveyed were found to contain the hybrid or Spanish bluebell. The survey drew attention to the threat posed to our native bluebell as well as the need for more research in order to better understand species distribution, gene transfer across species and appropriate horticultural management of bluebell species.
Thankfully, it has been illegal (without a license) for anyone to collect and sell native bluebells from the wild since 1998 as they are protected under the Countryside and Wildlife Act (1981). Current legislation allows for the issuing of a special license to collect wild seed for commercial sale. These safeguards ensure that collection is done sustainably and protects wild bluebell populations.
The native bluebell is a priority species under the UK BiodiversityAction Plan (BAP). Plantlife International states that it’s vital that the horticultural industry stop the deceiving sale of the Spanish and hybrid bluebell as native bluebell. Plantlife has also worked with Flora Locale to set up an industry code of practice. Flora Locale helps people get in touch with suppliers in their area who sell seeds of local provenance. Another initiative between Landlife and the Mersey Forest produces a legitimate source of bulbs grown from seed with a long term programme running to plant them in new woodlands. Plantlife International also gives advice about making sure that gardeners check suppliers of bluebells and how to remove Spanish or hybrid bluebells from your land – read more here.
The Natural History Museum launched a bluebell survey in 2006 (of which you can take part) to look at the extent to which non-native bluebells have spread into the British countryside. Results from the last eight years show that most bluebells in urban areas are now hybrids, but fortunately there are still large areas of countryside containing our native species.
Since 2010, the survey has concentrated on comparing the flowering times of native and non-native bluebells to understand how they will each respond to climate change. By comparing recent surveys with past data, it is possible to find out whether the flowering season is changing. These data need to be collected over many years in order to tease out any real effects of climate change from the natural fluctuations inherent in any population.

Sources:

[1] Grundmann, M. et al. (2010). Phylogeny and taxonomy of the bluebell genus Hyacinthoides, Asparagaceae [Hyacinthaceae]. Taxon, 59 (1): 68-82.
[2] Natural History Museum [website] Hyacinthoides non-scripta (British bluebell). http://www.nhm.ac.uk/nature-online/species-of-the-day/biodiversity/endangered-species/hyacinthoides-non-scripta/
[3] Pilgrim, E. and N. Hutchinson. Bluebells for Britain: A report on the 2003 Bluebells for Britain survey.  Plantlife International. <http://www.plantlife.org.uk/uploads/documents/Blubells-for-Britain-report.pdf>

More sources of information on bluebells:

Preston C.D. et al. (2002). New Atlas of the British and Irish Flora: An Atlas of the Vascular Plants of Britain, Ireland, The Isle of Man and the Channel Islands. ISBN: 9780198510673. [Provides information on each taxon]

Tines T.D.. et al. (2012). The Wild Things Guide to the Changing Plants of the British Isles. ISBN: 9781905026999. [Provides information on the spread of non-native bluebells]

The 2014 Easter Art and Sculpture Exhibition at the Botanic Garden

Posted on by andy.winfield
This is the second year in a row my family has worked off some Easter chocolate by biking to the University of Bristol Botanic Garden for the Easter Art and Sculpture Event. Unlike last year, however, when we were bundled against the cold, this year we basked in glorious sunshine. We’ve been so impressed with the quality of the art that this will be an annual event for my family…whatever the weather!
The Garden’s annual sculpture event was combined with the Friends of the Botanic Garden’s annual art exhibition, for the first time this year. This gave visitors a visual feast of outstanding artwork set in the backdrop of the garden in its full spring glory.

Over 2,800 visitors came to the gardens over the 4-day event. Events such as this, as well as the Bee and Pollination Festival, are important for the Botanic Garden as they reach beyond those interested in gardens – drawing in new audiences. This event brought in a range of West Country artists working in diverse mediums, from watercolours to ceramics and stained glass to metalwork – there was something for everyone.

Stainless steel sculpture of water lilies by artist Ian Marlow
Ian Marlow’s lilies were on display in the University
of Bristol Botanic Garden pond during the
Easter Art and Sculpture Exhibition.

A taste of some of the artists and artwork on display

One of the first pieces to catch my eye as I entered the gates of the garden was, of all places, in the pond. Stainless steel lilies, created by of Ian Marlow (www.marlowsculpture.co.uk), shone in the sunlight – a stark contrast to the dark water. Ian was also the creator of Sir Gromit ofBristol, which was certainly one of my son’s favourite stops along last year’s Gromit Unleashed trail.  

Willa Ashworth’s working display of one of lovely
metal open fire-pits offered warmth as well as
the promise of a sausage and hot cuppa.

Willa Ashworth (http://willaashworth.co.uk/) was there again this year, with a number of new pieces. I went home last year with one of her beautiful garden wind chimes and I still adore it! This year, she had one of her open fire-pits set up with sausages cooking on a grill and a kettle bubbling away. Her working display created a multi-sensory experience – the smell and sounds of sizzling food, the warmth and glow of fire, the beauty of the fire-pit itself. I watched as people gazed at the fire, no doubt envisioning (as I was) the lovely little set-up in their own backyard. Willa’s functional metalwork sculptures are inspired by her love of gardening and one of her pieces is now permanently displayed next to the lake in the Botanic Garden.

Karen Edwards (www.karenedwardsceramics.co.uk) was another return artist this year, displaying her nature-inspired ceramics. Each of Karen’s pieces are hand-built and unique. I was particularly attracted to her planters, which appealed to my functional side. The organic textures in the ceramics not only drew my eye, but beckoned me to reach out and touch them.

Karen explained how she created the lovely textures in one of her pieces:

One of Karen Edwards’ nature-inspired ceramics with
imprints of ammonites and bark.

“The doors of my studio are clad with unstripped half logs,” explained Karen. “I pressed some clay onto one area, then made that into a cylinder that I biscuit fired to use as a small hand roller. I then pressed in some shell and ammonite textures. The textures are highlighted with metal oxide wash and slip (liquid clay).”

One of Jude Goss’s stained glass pieces hanging in the
Chinese herb garden.

The Chinese herb garden once again hosted the stained glass art, including that of Jude Goss (www.lucianstainedglass.com). My six year old was thrilled to once again see Sam Bailey’s (www.theartistblacksmith.co.uk) metal dinosaur sculpture in the Evolution of Land Plants Display (nicknamed the grotto).

Stonecarver Tom Clark (www.clarkstonecarver.co.uk) had handed his chisel over to a pair of children when I got around to his display. The youngsters seemed to be having a brilliant time chipping away at the block of stone. Tom served an apprenticeship at Chichester Cathedral and has since worked on many large and interesting restoration projects including WestminsterAbbey and The National Gallery.

While I was circulating through the outside gardens, my husband managed to get into the glasshouses where he was captivated by the stainless steel pieces created by Julian P. Warren (www.metalgnu.com).

My son, Morgan, was equally enthusiastic about Julian’s work and he told me all about it on the bike ride home, with the unbridled enthusiasm that comes with being six.  “There was this amazing dragonfly mum…and a bird of paradise with those little sticky-up feathers on his head and everything!”

Sadly, I didn’t get to all the exhibits as I was keen on joining a tour set up by Andy and Nick for a number of bloggers (more on that below). I missed the botanical artists displayed in the Linnaeus Study room entirely! However, I have listed all the artists with links to their websites at the bottom of this post as they all made incredible contributions to the weekend event.

Oh…and I also got to hear about some delicious carrot cake on my bike ride home. Another thing I missed out on…the delightful refreshments being served on the newly finished west patio of The Holmes.

It wouldn’t happen were it not for the volunteers

As with any event of this magnitude, there is a whole lot of work that happens behind the scenes. With the Garden’s small staff, it is thanks to the many volunteers that it all comes together, and they are the first to admit it.

“It’s all those people out there that are welcoming people as they enter, giving tours, serving cake and refreshments and helping direct people around the garden that make this work,” said Nick Wray, the Garden’s Curator. “Without these volunteers, we simply couldn’t host important events like this.”

A personal tour for local bloggers

As part of the Garden’s plan to increase its digital presence and reach out to wider audiences, Andy and Nick hosted a tour of the garden for a number of local bloggers during the event.  Helen and I, both bloggers for the Garden, tagged along too!

We started in the meeting room with delicious cakes and a cuppa, while Nick gave everyone a briefing on the history of the garden, its core collections and more generally the role of botanic gardens. After lots of healthy discussion about the Botanic Garden and the role of social media in marketing, we all followed Andy into the garden where he briefed us on each of the main displays.

Fused and slumped glass artwork
Adele Christensen’s ‘Blomsters’: Fused and slumped glass
with mild steel support.

Despite having been to the garden many times before and having had lots of discussions with Andy and Nick…I still learned a great deal, and found new inspiration for blog ideas…so stay tuned!

Hopefully some of the other bloggers will have found some inspiration from the tour also – the Botanic Garden is, after all, a place for education and research, stewardship and conservation, but it is also a place of great beauty.

Artists on display were:

Susan Bracher (Email: susanbartle (at) blueyonder.co.uk)
Pamela Clogstoun
Anne Girling
Nick Hasell (Email: woodbarnfarm (at) hotmail.com)
Emma Jean Kemp (http://emmajeankemp.com/)
Florence Maggs
Betty Marten
Connie Ridge
Cynthia Skinner
Dorcas Sohn
Jac Solomons (aka J Zulka)
Sheila Southgate
Julian P. Warren (http://www.metalgnu.com/)
Frankie Wild
and

Refab Arts (http://www.bristolcreatives.co.uk/jobs/2010/05/19/reclaimed-fashion-genius-refab)

We’re gardenin’ in the rain

Posted on by andy.winfield

By Helen Roberts


It has been unbelievably wet since the start of 2014 with England experiencing it’s wettest January since records began over 100 years ago. The Somerset levels have suffered dreadfully and huge areas are still underwater and are likely to remain so for weeks or even months to come. From where I live, on the Mendips, I have far-reaching views over to Glastonbury Tor and the Quantocks and the area of levels in between looks like the vast inland sea it once was. In most other areas, the ground is completely saturated and in some places water is bubbling up to the surface.

Flooding in Greylake, Somerset in February, 2014. Photo
courtesy of Live-vibe on Flickr CC. 

What does waterlogging do to our gardens and what can we do to solve it?


Many plants do not like to be waterlogged because their roots need oxygen as well as water and nutrients. When roots are starved of oxygen they die and these dead roots can then act as a host for fungi such as Phytophthora, a root rot. Shrubs and fruit trees are particularly vulnerable to waterlogging as they cannot put on new roots as quickly as perennials and cannot stand long periods under water. Add freezing conditions with waterlogging and your plants may be in big trouble.
Winter flooding may not be fatal though, as many plants can experience and survive winter flooding for short periods of time. You can give your plants a helping hand if they’re waterlogged by pruning ornamentals right back so that they don’t have to protect so much above ground. You can also remove any dead or dying shoots and take cuttings as a back-up should the plant die. Smaller plants can be transplanted into pots with fresh compost, removing dead roots before transplanting.
Looking after waterlogged lawns is a different matter. If your lawn is squelchy to walk on at the moment, try to stay off it. Walking on it will only aid compaction and make matters worse. Waterlogged lawns can quickly lead to the grass dying and moss, algae, lichens and liverworts taking over. I do not have an issue with these plants in a lawn per se and I am not one to fret over weeds in a lawn either, but if you do want to make things better and improve a waterlogged lawn there are a number of options.

You can try pricking, spiking or slitting the surface of the lawn with powered tools or even a fork. This leaves holes that can be infilled with lawn top dressings or horticultural sand. It is best to get rid of surface water first, if possible, by sweeping it off with a brush into the borders. Otherwise, wait for it to drain naturally. Alternatively, convert your lawn into a water meadow!

Create a partnership with nature


Sometimes struggling against waterlogging in your garden or parts of your garden is a losing battle. It is simply better to accept the natural conditions of your garden and work with what you have. Rethink your palette of plants and cultivate those that favour wet soil. If the ground is permanently wet, consider establishing a bog garden as bog plants can be truly architectural in their habit and are excellent for attracting wildlife.

Some suitable bog species suggested by the RHS website include:
Herbaceous perennials: Bog primulas, Eupatorium maculatum Atropurpureum Group, Darmera peltata,Iris ensata ‘Rose Queen’, Iris laevigata, Ligularia ‘The Rocket’, Lobelia cardinalis, Rodgersia pinnata‘Superba’, Trollius x cultorum ‘Superbus’
Grasses: Spartina pectinata ‘Aureomarginata’, Carex elata ‘Aurea’
Ferns: Athyrium filix-femina, Matteuccia struthiopteris

A sustainable approach to managing flooding

How we manage water and excessive water in our own gardens, particularly in urban areas where there is nowhere to drain excess water, is very relevant at present considering the amount of rainfall we have had over the last couple of months.
Sustainable urban drainage systems or SuDS are approaches of managing surface waters taking into account quantity (flooding), quality (pollution) and amenity issues of water. They ultimately contribute to sustainable development and improve urban design. These systems mimic nature and manage rainfall as close as possible to where it falls aiming to slow water down before it enters watercourses. This is basically done by forming structures and landforms that can store water and allow water to soak into the ground, evaporated from surface water or lost through evapotranspiration. 

The use of SuDS is not by any means a new concept to ecologists, engineers, architects and landscape architects. It has been implemented very successfully worldwide and been effective in its way of managing water but also contributing significantly to the production of some truly innovative and outstanding design as well as creating areas of ecological value.

So how can you manage rainwater on a smaller scale in your own garden?

Nigel Dunnett, Professor of Planting Design and Vegetation Technology, and Director of the Green Roof Centre at the University of Sheffield is an expert in rain gardens and small scale rainwater management features. His research has looked at innovative approaches in planting design and landscaping that serve to store, collect and infiltrate rainwater runoff. Examples include the use of storm water or through flow planters, which are essentially raised, planted beds at the base of buildings that can take runoff water directly from roofs or adjacent areas of hardstanding.
The key to Dunnett’s research is that it can be replicated on a small scale in one’s own garden and can be just as effective in terms of its aesthetic and ecological value, particularly in urban areas.
Other approaches to managing rainwater include reducing runoff from hard surfaces, such as driveways and patios, by using permeable paving that allows water to soak directly into the ground. Roofs on sheds and garages or any external outbuildings in the garden could have green roofs installed. Furthermore, you could use Dunnett’s techniques of creating rain gardens and create a truly sustainable garden that works with nature and not against it.
Nigel Dunnett was a recent speaker with the University of Bristol Botanic Garden Friends’ Lecture series.

An interview with Mark Bolton: photographer, traveller, cider-lover and allotment dweller

Posted on by andy.winfield
It was nearly a year ago when I first emailed professional photographer Mark Bolton about an interview. He’s a busy man. However, last week our schedules finally meshed and we got to chat on the phone about his lifelong passion for photography, his love of gardens and his long-time connection with the Botanic Garden.
Of course, before I spoke with Mark, I had a thorough look at his website (www.markboltonphotography.co.uk), trying to glean as many details about him as possible so as not to waste too much of his time. There is, as one would expect, an outstanding portfolio of his commercial photography – extravagant hotel interiors, delicious food, immaculate homes and exquisite gardens. However, it is the images under his “personal” tab that have me intrigued and perhaps provide a glimpse into the man behind the camera – a traveller, a cider-lover, and a gardener. There are images of frequent visits to East Prawle that spark a thousand questions in my mind: I want to know the lady in the outrageously colourful camper and what the man with the binoculars is looking at…and tell me the story behind that dog! I’m looking forward to the interview.

A lifelong passion

View of the Holmes. Photo by Mark Bolton.

Mark has been a professional photographer for over 20 years and photography has been a passion for as long as he can remember.
“My dad gave me a camera when I was a young teenager”, said Mark, “and I never really wanted to do anything else.”
Mark started off as an assistant to a well-known interior photographer. However, he quickly realised that the same magazines that were buying the house and home interior shots were also looking for garden images. As he had always been inspired by nature, he thought he would have a go at garden photography.

Connections to the Botanic Garden

As with any skill, photography takes practice. Being Bristol-based, Mark started to go to the Botanic Garden at the Bracken Hill site to practice photographing plants.
“I used to go almost every day,” said Mark. “I would go in early in the morning before anyone got there and when the light was best.”
Mark hesitantly admits that he misses the Bracken Hill location – an emotional tie to the place where his successful career blossomed (that’s my awful pun…not his). Today, Mark is still a frequent early-morning visitor to the Botanic Gardens. Each visit presents itself with different light, different backgrounds, and seasonal changes that create new opportunities for photography.
It was also Mark’s familiarity with the garden that prompted him to suggest to his dad, Colin, that he consider becoming a volunteer gardener. Colin has now been volunteering with the garden for ten years.

The challenges of garden photography

Frosty flowers. Photo by Mark Bolton.

Before I even get to ask the obvious question about the challenges of garden photography, Mark starts to tell me how the market has changed over the years. When he started out it was easy to sell garden images. However the internet, the move to digital platforms and a plethora of amateur and semi-pro garden photographers has changed the game, diminishing that particular income stream.
Aside from the greatest challenge of making money doing it, garden photographers must also face the elements. Having experienced significant hail storms and veritable downpours in the last 24 hours, I would imagine that working in the UK can be particularly frustrating at times.
However, it is the garden photography that he loves, and Mark hopes to do more in the coming year. When compared with some of the other commercial work that he does, Mark says that with garden photography “there’s no styling – you just have to look for the picture”.

Mark’s second office

During the busy season between April and October, Mark spends at least three days a week out photographing. Then there is considerable time spent at his computer processing the images. Whatever time he has left Mark spends at his second office – his allotment.
“Photography is not a 9 to 5 job,” said Mark. “I always have a camera with me.”
Even at the allotment. In fact, Mark admits that he will plant things with a view of making a picture – considering aesthetics as much as the practical needs of the plants.

The details

Mark visits the Botanic Garden in the early morning, before
visitors arrive and when the lighting is better.
Photo by Mark Bolton.

I couldn’t possibly write a post about photography without satisfying the needs of those wanting the technical details…so here they are. Mark’s equipment of choice at the moment is a Canon EOS 6D with a mix of lenses, but for a lot of his garden work he uses a 100 mm macro lens. Other than that, his equipment list essentially consists of the mandatory tripod and a piece of small white card for adding some reflective light when necessary.

Though it’s unlikely that you’ll get to see Mark practicing his art in the garden as he has usually come and gone before it’s open to the public – you can see some of his work on his website and in any number of publications such as The Telegraph, The Guardian, Homes and Gardens, House and Garden, and Country Living (to name only a few). He has also been kind enough to share some of his work from the garden for this blog post…so, please enjoy!
Photo by Mark Bolton.

Photo by Mark Bolton.