Category: horticulture

Botanic gardens: places of research, education and beauty

Posted on by andy.winfield

By Nicola Temple

There are an estimated 3,400 botanic gardens around the world, many of which are associated with universities or other research institutions. This association with research institutions can give the impression that these gardens, Bristol’s own Botanic Garden included, are primarily research oriented and not particularly appealing to the public – nothing could be further from the truth.

In the last two years that I’ve been blogging for the Botanic Garden, I have taken myself to Kew Royal Botanic Gardens, Tresco Abbey Gardens in the Isles of Scilly, El Charco del Ingenio Botanical Garden in Mexico and the University of Alberta’s Devonian Botanic Garden. I’ve been keen to see how they differ from my local Botanic Garden that I’ve come to love. These gardens have been different in their sizes and plant collections and clearly differ in their annual budgets, but they have all been united in their commitment to educate and they have all been beautiful places to spend a day (or two).

The history of botanic gardens

One of the many spectacular species of orchid on display
at Kew Royal Botanic Gardens. Photo credit: Nicola Temple.

Botanic gardens seem to first make an appearance in the 16th century. They were set up largely as medicinal gardens where research and experimentation could be carried out on medicinal plants. They were often associated with medical schools and universities of the time.

In the 17th and 18th centuries, the focus of research changed as global exploration started to bring back new exotic species of plants. Some of these plants were medicinal in nature and were of interest for that reason. Some, such as spices, were of interest because of their economic value. Some were simply of interest due to their exotic beauty and many of the wealthiest families wanted specimens for their own collections. In the 18th century glasshouses and heated conservatories were built in some of the botanic gardens in order to keep some of the species alive that were being brought back from tropical habitats.

A corridor through the Agapanthus at
Tresco Abbey Gardens. The species was
introduced to the Isles of Scilly by the
proprietor of the gardens in 1856.
Photo credit: Nicola Temple.

The research focus of botanic gardens has continued to evolve to meet the needs of society. Today conservation, climate change and sustainability are the greatest challenges we face and as a result, many botanic gardens around the world have active research programs in these areas.  The decades, and in some cases centuries, of information collected by these gardens is proving incredibly valuable in terms of how the climate is changing and how some species are responding.

Botanic gardens play a critical role in conservation

In 2010, the Conference of the Parties to the Convention on Biological Diversity adopted an updated Global Strategy for Plant Conservation (GSPC). The University of Bristol Botanic Garden, along with botanic gardens around the world support this global strategy in every aspect of the work that they do.

The strategy recognises that without plants, life on this planet would cease to exist. The aim, therefore, is to halt the continuing loss of plant diversity. The five main objectives of the GSPC are:

  • Plant diversity is well understood, documented and recognised.
  • Plant diversity is urgently and effectively conserved.
  • Plant diversity is used in a sustainable and equitable manner.
  • Education and awareness about plant diversity, its role in sustainable livelihoods and importance to all life on Earth is promoted.
  • The capacities and public engagement necessary to implement the strategy have been developed.

The El Charco del Ingenio Botanical Garden in San Miguel
d’Allende, Mexico had many parts that were less formal than
other botanic gardens. Photo credit: Shelby Temple.

The University of Bristol’s Botanic Garden developed the Local Flora and Rare Native Plant Collection in response to the GSPC. In the eight habitat themed displays associated with this collection – Carboniferous Limestone grassland, woodland and cliff face (found locally in the Avon Gorge & Durdham Downs, Mendip Hills and North Somerset cliffs and coastal islands), Coastal Communities, Deciduous Woodland, Aquatic and marginal areas, hedgerows and seasonally flooded sedge peat meadow associated with the Somerset Levels  – are many of the rare and threatened native plants to these regions. The Garden is therefore a global repository for this plant material in both these living collections as well as its seed banks. Over the coming months, Helen and I will blog about each of the Garden’s collections in more detail, so stay tuned!

A place for learning

Cactus in flower at the El Charco del Ingenio Botanical Garden.
Photo credit: Shelby Temple.

The plant collections at the Garden are used extensively by the University of Bristol for undergraduate teaching as well as in graduate student projects. Beyond this, however, it is a place to learn horticulture, art, photography, garden design, and numerous skills from willow weaving to wreath making.

Formal courses and training through the Royal Horticultural Society are also held at the University Botanic Garden – it’s an ideal setting.

The Garden also offers tours – whether it’s a special interest group, school group or a group of friends wanting to join one of the summer evening tours. Having joined on a school group tour in the past, I know the volunteers are very good at tailoring the tours to draw together information the children have been learning in class with the collections on display.

A place to be inspired

A pollinator drinking nectar from milkweed (Asclepias syriaca)
flowers at the University of Alberta’s Devonian Botanic Garden
in Canada. Photo credit: Nicola Temple.

The collections, knowledge and expertise held at the Botanic Garden puts it in an ideal position to raise public awareness of the plants on display, our interdependency on plants more generally and critical issues facing many of these species, including changes as a result of global warming, habitat loss and invasive species. These are common threads in all of the communications put out by the garden.

More than this though, the Bristol Botanic Garden aims to foster an interest in plants and inspire people through its work. We can all feel somewhat paralysed by the plethora of environmental gloom and doom stories sometimes. Sometimes inspiration and awe about a species can spur people into action more easily than anger and frustration. The Garden’s annual Bee and Pollination Festival is an excellent example of this. Pollinators are having a tough go of it and a National Urban Pollinators Strategy is under development in the UK as I write this to try and improve the situation for this critical group of animals. All the important information is at the Festival, but overall this is a celebratory event – an opportunity to learn and get excited about how amazing pollinators are and how we are so deeply connected to them in so many aspects of our life.

A sunflower display at the Devonian Botanic Garden, Canada
was very popular with the butterflies. Photo credit: Shelby Temple.

The Garden can also be a quieter source of inspiration. I have now spent many hours sitting with camera in hand trying to get perfect flower shots or just simply watching bees move from flower to flower. Sometimes inspiration can be found in these quieter moments, surrounded by beauty, in a garden in a city.

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.

‘Tis the season of seed cleaning

Posted on by andy.winfield
Weeks ago, Nick suggested I come in on a rainy day to the garden as there was lots of seed cleaning going on in the potting shed. Then it didn’t rain for three weeks. Defeated by the glorious Autumn weather we’ve had, I phoned Froggie, and asked whether I could come in to learn about seed washing…yes, that’s right, I said “washing”. I’m such an amateur! However, Froggie was kind and  refrained from laughing at me and just said, “we don’t really wash the seeds unless they have a particularly fleshy covering”.
We arranged a time for me to come in and, as it happened, it was yet another glorious sunny day. While this made for a nice bicycle commute for me, it meant that the volunteer gardeners were all out in the garden so I would be having an individual, hands-on learning experience with respect to seed cleaning.

So many envelopes

As Froggie and I entered the potting shed, she took me immediately over to a bench lined with trays in which rows of envelopes were stacked up. On the outside of each envelope is written the plant’s latin name, the family name, the year the seed was collected, which collection the plant is from, the accession number and a number that corresponds with its numbered listing in the Garden’s Index Seminum. This is a catalogue of the seeds and spores that have been collected in association with the University of Bristol Botanic Garden. This catalogue goes out annually to the Friends of the Garden, other Botanic Gardens and research institutes. Requests can be made for small quantities of seed for the purposes of research, breeding, conservation and education, or by members of the Friends of the Garden (subject to certain conditions).
The Garden likes to keep three years worth of seeds, but obviously different seeds have different storage potential. Some species, such as those in the Apiaceae family, which includes celery and parsnips, are generally only viable for a year, while other seeds have been found in archaeological digs that are estimated to be thousands of years old and have remained viable (see the 2,000 year old Judean date palm as an example).
Separating the seeds of Salvia forsskaolii. 
“We’ll keep back older years from groups such as the cereals, oats and wheat, as well as beans and peas,” said Froggie, “as they will likely remain viable and it’s good to have a reserve.”
Froggie explains that with the Garden’s involvement in the Seeds of Change project, there are even more demands on their seed stores. Though schools and community groups are encouraged to collect their own seed, the Botanic Garden is sending out lots of seed to start the projects off or replenish projects where collection efforts haven’t been successful.
In the little office at the back of the potting shed there are even more trays of seeds. This is where the staff compile all the seeds that go on the Botanic Garden’s annual seed list. Now having a sense of what the end product looks like, I sense that Froggie is about to show me how much work goes into filling each of these envelopes…

Separating the seed from the chaff

Pouring the Salvia seeds into a sieve to get
rid of the chaff.
I’m shown yet more trays of envelopes – but much bigger envelopes this time – many with stems poking out the top. The gardening staff and volunteers have collected the seed heads and placed them in these envelopes ready for cleaning and this is where the work begins. Froggie picks out the first envelope, it’s Salvia forsskaolii, commonly known as Indigo woodland sage.
We sit at the table, each with a white tray nestled within a larger black tray, which I assume is to collect the seeds that catapult out beyond the borders of my white tray. Froggie doles out a few sprigs of dried plant and shows me that the best technique for this particular plant is a simple flick of the seed head to help release the seeds. I flick and my white tray is scattered in small black seeds. Easy.
With the larger unwanted bits removed, we now pour our tray contents into a sieve to clean the seeds of any smaller bits. The clean seed is then poured into a smaller envelope that is placed back into the big envelope with the remaining plant material that is yet to be cleaned. When all the plant material has been worked, Froggie will then process the seed envelope, doing and final quality control check on the seed and making sure all the information is clearly written on the envelope.  
Nigella damascena before we begin to collect the seed.
We wipe down our trays and spray an anti-static spray to ensure there is no contamination as we move on to our next species – Nigella damascena. This too requires a tapping method, though some persistent seeds need to be squeezed out. There are numerous implements on the table for crushing plant material to get at the seed, but Froggies says they try to discourage crushing as much as possible as it makes for a lot of fine chaff that is difficult to separate out later.
As we work, Froggie fields questions from the volunteer gardeners who are looking for equipment or just confirming that what they’re doing is right. As we work, Froggie relays a few stories about misguided efforts of volunteers – stories of pruning gone awry or cutting back incorrect species – she chuckles about it all and has an ‘it all grows back’ sort of attitude about it. I know Froggie no doubt has a million other things she needs to be doing, but she gives me her full attention and focus and makes me feel as though she has all the time in the world for me. She creates a calming atmosphere, which no doubt comes in very handy when coordinating the efforts of so many volunteer gardeners and teaching new skills.
What my tray looks like after I’ve removed the Nigella seeds
from the seed heads. 
There is quite a bit of fine material mixed in with the Nigella seeds and so Froggie introduces me to another technique for separating seed from chaff. She takes some newspaper and folds it in half and pours seed and fine chaff together onto the paper. Then with a motion not dissimilar from a chef tossing almonds in a skillet, she carefully tosses the seeds in the paper. The fine, lightweight chaff moves to the top of the crease in the paper, while the heavier seeds move down. She can then simply give a very gentle blow to get rid of the chaff off the top of the paper. In the end she’s left with just the clean seeds.
We start on the last one – Avena orientalis – a grass. For this seed you hold the spikelet in one hand and flick the seed out. This particular species has a lovely dark seed, so it is very clear when you’ve got it all separated. 
Froggie uses newspaper to separate the lightweight chaff
from the heavier Nigella seeds.
Not all the seed cleaning is this easy. There are dust masks as some can be particularly dusty – but the staff tend to do the really nasty seed cleaning themselves, letting volunteers do the easier ones. If this were a rainy day, there would be volunteers everywhere working on this and having a good old chat.
Looking at the stacks of envelopes, I ask Froggie when seed cleaning needs to be finished.
“We need it all complete by February at the latest,” Froggie replies. “The seed list goes out in February and people will start to put requests in. We also start sowing at the end of February, beginning of March.”

Checking the lists

Cleaned Avena orientalis seeds with the
lighter leftover spikelets in the background.

In many of my excursions to the garden, the staff have introduced me to the many lists that they keep. There is a seed sowing list, a putting the garden to bed list, and now, I have seen the seed collecting list. This is where the staff make notes against each species – for example, if a plant was too small or late to come into flower. These notes are kept year to year and so if a species is less productive in one area of the garden than another or from one year to the next, all of this information is captured.
“The list is never finished,” says Froggie. “I will just update it when something else changes.”
In years where they are unable to collect seed for a particular species, they draw upon their reserves from previous year so that it can remain on the seed list. Annuals tend to be a priority, but also shrubs. The Garden works hard to insure that there is variety on the seed list.
As a member of the Friends of the Garden myself, I now look forward to receiving the seed list next year and I will have a much better appreciation of the work that goes into collecting the seeds for each of the nearly 200 species listed.

RHS Courses: Getting practical in the garden

Posted on by andy.winfield
It’s Saturday morning at 9:30 and as I walk into the classroom there are fifteen small plates filled with different types of seeds lined up around a table. Along one of the walls, flowering plants are lined up as well. I recognise a few of the flowering plants but even then I wouldn’t know the Latin names and I recognise even fewer of the seeds. I’m incredibly glad that I’m not taking the test.
I’ve come to sit in on the RHS Level 3 course ‘Certificate in Practical Horticulture’ that is currently running at the Botanic Garden. The course has been running every Saturday from 10am until 4:30pm since the 18th of May and it will continue until the end of August.
The course is taught by a number of tutors who teach for a block of seven weeks or so and it covers core units that include collecting and testing soil samples, collecting, preparing and propagating from seed, and identifying a range of common garden plants, diseases and disorders. The course is a balance of theory and practical and so students get to practice all the skills they learn in the classroom. Today, the students will be doing some seed and plant identification and then will be going outside to do some pruning.

Life experience brings added value to RHS courses

The teacher today is Chrissy Ching, a freelance horticulturalist who has been teaching RHS courses for over six years. When Chrissy isn’t teaching and running her business, she’s also being a student herself. She’s an MSc student at the University of Bath in Conservation of Historic Gardens and Cultural Landscapes, so she’s sympathetic to the demands on adult students.
No pictures of the RHS course, but I made a quick visit to
the glasshouse to see the lotus in bloom…beautiful!
Chrissy’s first involvement with RHS courses was as a student. She was an accountant when she first started taking RHS courses. “I thought I was doing it for interest originally,” said Chrissy. However, it eventually led to a complete career change.  Many of the students taking the RHS courses are also career changers and so this added dimension of life experience that Chrissy brings to the course is added value for many of the students.
But, it’s not only Chrissy that brings life experience to the course. The students themselves come from diverse backgrounds, whether in horticulture or not, and add to the learning experience also.
“I think the students learn as much from each other as they do from me,” said Chrissy.

Teaching RHS courses at the Botanic Garden

This is Chrissy’s first time teaching an RHS course here at the University of Bristol Botanic Garden though she has taught classes a the Birmingham Botanical Gardens and numerous college and city gardens. She sees this as a wonderful opportunity for the students.
“This is a living, breathing garden with a rich diversity of plants,” said Chrissy. “This gives the students a great way to study plants and especially taxonomy.”
Of course, she also points out that because the Garden is open to the public, it also has to look attractive. Therefore, it isn’t always ideal to have unskilled students practicing horticultural skills such as pruning. Luckily, Chrissy is there to help guide the process.


Motivated by tests and inspired by previous generations

As I’m there early, I take the opportunity to speak to some of the students before the class starts. Emma is the first student to arrive. She’s a young woman with a background in graphic design. She decided to take the course for interest as she secured an allotment about six months ago and wanted to learn more about gardening. She also thought it might provide some accreditation should she wish to shift careers, ideally combining her background in graphic design with a love of gardening to eventually get into garden design. 
This is the first RHS course Emma has taken. She was allowed to enter level 3 due to her academic background, however she admits that it’s been quite demanding at times.
“I wanted to take the course as I knew the challenge of tests would motivate me and stimulate my mind,” said Emma, “and it has. There’s been more theory to the course than I thought there would be and learning all the Latin names has definitely been tricky.”
Emma was inspired to take the RHS courses by her granddad who also did RHS courses and made a career in horticulture.

Enriching an existing career 

I slide over to talk to Darren as I’ve asked Nick, the curator of the Botanic Garden, to point out someone who’s here that works in the industry.  Darren is originally from Perth, Australia and has been in the UK for around nine years. For the past nine months he’s been working for a landscape gardening company and prior to that he worked for a gardening centre.

This is Darren’s 3rd RHS course and he started taking them because he was getting lots of questions from customers at work and he wanted to have the right answers. He’s here to enrich and further his existing career. That being said, so far, Darren has footed the bill for the courses himself, not to mention the significant time commitment that’s required.
However, for Darren, the courses are well worth it. He’s been impressed by the enthusiasm and wealth of knowledge from the tutors as well as the other participants in the class.
“It’s good to have a group of people who are like-minded,” he said, “to talk about the things that you’re interested in.”
Mimosa is also in bloom in the glasshouse
right now – they’re like a little fireworks display!

Well-worth the commitment

Unfortunately I’m forced to leave the course less than an hour in. I have my five year old with me as it’s school holidays and his patience for horticulture is fairly minimal. However, what strikes me most as we jump on our bikes to spend the rest of this beautiful Saturday seeking out Gromit statues around the city, is the commitment these students have.
Most of these people have jobs, yet for nearly four months they have committed one day of their weekend to this course. Whether motivated by improved career options or by an interest in gardening, for them, this course is worth the commitment. For me as an outside observer, this speaks volumes.

If you are interested in learning more about the RHS courses taught at the Botanic Garden, please visit the website for more information.