Category: seasons

Re-potting lotus ready for the new growing season

Posted on by andy.winfield

The lotus plant is a symbol of friendship, family, rejuvenation, hope, rebirth, fortune, purification and positivity. The rhizomes of the plant lie buried in the sludgy, smelly mud on the bottom of lakes and ponds. Rising up from the mud are the leaves and the strong stems, which come up through the water to support the heavily scented, beautiful flowers. This pattern of growth makes the lotus a very important and powerful symbol in Buddhism. It signifies the progress of the soul as the flower rises from the primeval mud of materialism, through the waters of experience, and into the bright sunshine of enlightenment (source). Though most water plants send blooms to the surface in this way, only the lotus flower sits up to one metre above the water’s surface, truly rising above it all (source).

Lotus are a primitive plant. The fossil record shows that 15 million years ago there were eight different species of lotus, which were later reduced to only two species – the Asian lotus (Nelumbo nucifera) and the American lotus (Nelumbo lutea). The spiritual, nutritional and medicinal importance of this plant in Chinese, Vietnamese and Indian cultures has made it the focus of extensive research and breeding programs. There are over 500 different cultivars of lotus in the world and the University of Bristol Botanic Garden has carefully chosen cultivars that show the range of flower forms and colours for its small collection.

Last week I met Penny Harms, Glasshouse Coordinator at the Botanic Garden, in the potting shed to see what she’s doing to prepare the Garden’s lotus collection for the next growing season. Penny and her team pulled the lotus plants out of the pond in October, where they have been sitting dormant in their pots ever since. Now, it’s time to give them some attention and get them ready to go back into the pond.

Penny is very careful when cleaning
the lotus rhizomes as any damage will
affect its growth.

Looking after Lotus

First, Penny tips the pots out, getting rid of all the old soil and gently collecting the lengths of rhizomes that wind around in circles within the pots. The rhizomes are then placed into plastic trays with lids that have holes to ensure they don’t get moldy. Over several days, Penny then sorts through each of the trays and pulls off any of last year’s rhizomes, which are brown and rotten compared with the cream-coloured healthy rhizomes.

“You have to be really careful,” explained Penny. “These are the growing shoots – this is a leaf here – so if you damage these, the plant won’t grow very well this year.”

Once the rhizomes have been cleaned they are potted up. Penny has prepared a special mix which is a loam-based potting mix to which she adds Bracken Down – a mixture of thoroughly composted bracken, bark and manure – and Osmocote – a controlled release fertilizer.

“Osmocote releases its nutrients over 18 months in a normal pot,” said Penny, “but because the pots are going into a really warm tropical environment, this will speed up considerably. It will release the nutrients over the summer, which is quite handy as these are quite hungry plants.”

Bonemeal is also added to the soil to give added support to the roots and chicken manure pellets are also added to provide more food. The lotus plants replenish themselves each year, so all of the rhizomes Penny showed me will be completely replaced by new growth this year. If the soil doesn’t have enough food and the temperature isn’t warm enough, the plants get weak and don’t really do anything.

“Last summer was quite poor,” said Penny “which meant there was less light and the glasshouse didn’t get as hot. We noticed that the quality of the rhizomes has gone down this year. I record the quality of the rhizomes when I pot them up and we’ve had some really strong rhizomes in the past. But this year, they don’t seem to have done anything – it’s as though they reached a growth plateau.”

Trays of lotus rhizomes. The tray on the left hasn’t had
the old material removed yet, but the one on the right has
been cleaned and is ready to be potted up.

Placing lotus by the poolside

After the lotus have been potted up into clean pots with all new soil, Penny will write new labels and bring them into the tropical house. The pots then stand in trays of water along the side of the pool. This keeps the soil constantly wetted and after about a week of being in 25oC temperatures, the plants come into growth.

Once the leaves are 3-4” high and there are enough of them that Penny knows the rhizomes are growing, she raises the water level of the pool and moves the pots down onto a lower edge along the pool. This keeps the pots submersed in the warmest upper layer of water.
For the final phase, the pots are moved into the main pool where they sit on top of a stack of mesh trays. The water level is raised again so that it covers the top of the pots, but this has to be timed as well with the growth of the giant water lilies (Victoria) that occupy the large planters in the pond.

“Then that’s it for spring and summer,” said Penny “and I have to just cross my fingers that they do their stuff and produce beautiful flowers.”

The many uses of lotus

The rhizomes of lotus are rich in sugar and starches and contain up to 2% protein. They are sliced and roasted, dried or pickled. For medicinal purposes the rhizome is made into a juice or steeped in a tea and taken topically or ingested to stop bleeding.
The disc-shaped leaves and stems are eaten raw or used to wrap other foods, such as rice, for cooking. Medicinally they are taken to clear fever.

The flower has many uses. The outer covering of the flower – the calyx – is used in medicine. The petals of the flower are eaten and the male stamens are used to flavour tea and also contain the fragrant essential oil, which is extremely coveted. Lotus oil is three times more expensive than gold weight for weight. The receptacle, which houses the female parts of the flower and eventually the seeds, is aged and used for medicinal purposes.

The young green seeds have up to 16% protein content and are considered quite a delicacy. They can also be ground into flour to make bread or used medicinally to stop incontinence and digestive problems. The green shoots from the seed – known as the plumule – can also be removed and used for medical purposes.

There’s a lot in a name

When you visit the lotus display in the tropical glasshouse, you will notice that each of the labels has a series of names. At the top is the latin name (e.g., Nelumbo nucifera), then beneath that is the Chinese name (e.g., Xiao Foushou) and the translation (e.g., Small Buddha’s hand). Finally, along the bottom of the label is a description of the flower type (e.g., pink cup lotus). Chinese lotus flowers range from pink to white and some are cream or with a hint of green, but there are no yellow flowers in the Chinese lotus species. Yellow flowered cultivars, originate from the American lotus lineage.

The Botanic Garden has recently ordered some new cultivars from China to expand their lotus collection, including a yellow-flowered cultivar of the American lotus.
Date holder: Mark the 19th of May in your calendars as the Botanic Garden will be hosting a Fascination of Plants Day event. 

The scent of winter

Posted on by andy.winfield

The last remnants of snow that recently blanketed Bristol, and indeed most of the UK, have been washed away by what seems like relentless rain. In the Botanic Garden, the staff and volunteers are seeking shelter in the potting shed and glasshouses, turning to indoor work during this inclement weather. Yet, despite grey skies and soggy soil, the Garden still has some delights to offer the senses.
Prunus mume in bloom at the Botanic Garden
Just outside the welcome lodge at the Botanic Garden, there is a delightful fragrance emanating from the Chinese plum, which is also known as the Japanese apricot (Prunus mume). This is an incredibly important plant in China and Japan and the delicate pink flowers feature prominently in much of the art from these cultures. Beneath the Chinese plum, Helleborus is in bloom – purple, pinks and whites – offering a beautiful winter display of colour.
Andy, a botanical horticulturist at the Garden, has taken time out of his busy schedule to show me around today…in the rain. As we enter through the main gate, all the borders are looking incredibly tidy. Now that the last leaves have fallen, the volunteer and staff gardeners have taken the time to sweep and rake up the remains of autumn.
Snow drops have finally made their appearance.
Andy takes me past the pond to an area at the back of the garden where the gently sloping grass bank is scattered with spring bulbs that have broken through. Andy explains plans to make a bee hotel. There is already a good stack of wood and bamboo started, which will be added to over the next while to provide habitat for solitary bees. There are also plans to use some planks to create a city skyline sculpture that is also fully functioning bee habitat – a ‘Bee-tropolis’ if you will. Good gardeners always treat their pollinators well!
Winter sweet (Chimonanthus) looking a little soggy.
We stop at the winter sweet (Chimonanthus) and have a smell of the small white flowers that are growing along the bare branches. Andy tells me that most of the winter flowering plants are incredibly fragrant in order to attract the few pollinators that are out and about at this time of year. Unlike the sweet smelling Chinese plum, the winter sweet has a more nutty or spicy scent, which makes me wonder what sort of pollinator it’s trying to attract. Generally speaking, flowers with a spicy or fruity smell tend to attract beetles, while sweet smelling flowers attract bees and flies.
The winter flowering honeysuckle (Lonicera purpusii) is in full flower. The flowers are…subtle. In fact, Andy needs to point one out to me. It has a strong citrus smell that is really lovely.
Winter flowering honeysuckle (Lonicera purpusii) 
has a lovely citrus fragrance.

Without a doubt, however, the amazing winter display is the evergreen Daphne bholua ‘Jacqueline Postill’. It is in full bloom and is incredibly fragrant. This species grows wild in the Himalayas and belongs to a group known as the paper Daphnes as the bark was once used to make paper and rope.

Beyond the Daphne, in the corner, there are a number of very large wheelbarrows filled with branches and cuttings that are evidence of how much cutting back and clearing has been done in the garden recently. There is also a pile of branches and a bush, which are all victims of the recent snowfall.
Daphne bholua ‘Jacqueline Postill’
offers an incredible winter display.
“Winter is a time for keeping our fingers crossed,” says Andy, “hoping that everything makes it through and that all the winter protection we did helps.”
As we cruise by the compost heap, I can’t help but think of the rotting robot parts.
Beyond the compost and the vegetable patch, there are piles of Hazel branches. The gardeners have been collecting these in preparation for the new growing season. They are used as pea sticks to support herbaceous plants. It’s one of many winter tasks in the garden.  
Andy explains that winter is when much of the landscaping and development is done in the garden. However, right now with such sodden conditions, it simply can’t be done. But, in the meantime, there’s lots that can be done indoors. Let’s hope the winter pollinators have more luck with their outdoor tasks!

Putting the garden to bed

Posted on by andy.winfield

We all have different approaches to our gardening. Mine is very much a ‘survival of the fittest’ style. You will not find any high maintenance plants in my garden and it’s not from a lack of interest – it’s merely a reflection of my personality and lifestyle. However, when you house over 4,500 species from all over the world, as the Botanic Garden does, there needs to be some serious plant coddling. Particularly at this time of year as the days get shorter, temperatures drop and rain is inevitable.  Plants that are adapted to winterless weather need some special attention and so the staff and volunteers at the Garden are very busy right now putting the garden to bed.
Andy Winfield, a botanical horticulturalist who’s been working at the Botanic Garden for nearly twelve years, toured me around last week to show me some of the special treatments the plants are getting in preparation for winter. The first stop…bananas!
A few weeks ago when I was here, these banana plants were lush and green and reminding me of tropical places. Now there is no sign of that lush foliage, and some intriguing looking tee-pees stand in their place.
The banana plants are prepared for
the winter ahead beneath many
layers of insulation.

 “We start with a framework of bamboo,” explains Andy, “then around that we put some stiff plastic to form a funnel, which we push loads of straw into, down around the trunk of the plant. On top of that we put a little plastic hat to stop the rain coming in and soaking the straw. The leaves of the plants have been cut right back, so it’s the trunk that we are protecting over the winter. If rain gets in and the plant isn’t putting on any growth due to the cold weather, the trunk will just turn to mush.

“Then around the plastic cone, we wrap some fleece. Finally, we wrap the bamboo supporting structure in green netting, which goes around and encompasses the whole lot. We also pile bark mulch around the base of the plant to protect the roots.”
This process will take two people nearly an entire day to wrap three trees. It’s a labour of love to be sure, but it’s also a tried and true method. They’ve been using this method at the Garden for years -through wet winters, cold winters, and even really cold winters, and the bananas have come through it all.
The leaves of the Gunnera manicata are placed over the
the crown of the plants as part of the winterising process,
which also gives an interesting display.
Next on the tour is the Gunnera manicata, commonly called giant rhubarb. The giant leaves of this Brazilian native, which normally dominate the pond area have all been cut back and inverted into what can only be equated to little hobbit-like homes.
“This plant wouldn’t normally have a dormant period where it’s from, but here we need to protect it through the winter,” said Andy. “It has a great big crown, which is the growing point and that is what we need to protect. So we cut off all the leaves, and cover the crown in bark. Then we keep the bark in place by using the leaves as a cover. We tie a number of them together and invert them over the top, then firm them in place with more bark around the outside. It’s functional, but it also provides a structural display.”
As we walk past some cloches placed to protect some dry-loving Mediterranean plants from our wet south west winter, Andy explains some of the process behind putting the garden to bed.
“We consider each plant individually – where it comes from and what its needs are. Then we have a think about how best to protect it over the winter.”
Cloches protecting plants from the
wet of winter.
In fact, they have a list at the Garden with every species named along with very specific instructions for preparing it for winter. I’ve seen this list – it’s 21 pages long! Each year, Nicola Rathbone one of the horticulturalists at the Garden, goes around with the previous year’s list and updates it – adding new arrivals to the list and taking the less fortunate off. Then, it’s a matter of setting to work and starting with the most vulnerable plants, like the cycads and bananas, first. Work starts just before the first threat of frost, which was October this year, and by November things are in full swing.
Next, Andy takes me into the evolutionary dell – one of my favourite parts of the garden. The tree ferns haven’t had anything done to them yet, but shortly they will have some straw stuffed into their crowns and a little plastic hat placed on top to protect them from any penetrating cold or frost. Andy and the other staff keep a close eye on the weather in the winter and if a prolonged cold spell is in the forecast, the tree ferns will also get wrapped in fleece to insulate their trunks from the cold.
Some of the cycads, which are buried in the garden in pots, have been lifted, pot and all, out of the ground and placed in the glass houses. A couple of these plants have been a part of the garden for over 60 years and are substantial in size, and so this is a considerable job to transfer these individuals, and it’s all done by hand. The more hardy cycads are left in the ground and given the same treatment as the banana trees.
Branches are swaddled to protect them from winter frost.
As we walk out of the dell, my eye finally starts to tune into the individualised approach that has been taken to protecting the Garden’s investments. There are ‘mummified’ trees and shrubs that have had their trunks and branches swaddled in cloth to protect them from the cold. Little glass domes peek out randomly throughout the garden and some of these cloches are filled with straw, to give protection against the cold as well as the wet. Some plants, such as the Daphne bholua ‘Jaqueline Postill’ have a wall of netting on only their north-facing side to protect them from cold north winds, while other plants are completely surrounded by netting.  One of the volunteers, Sue, is hammering in a netting screen as we walk by.
“It’s a huge job putting the garden to bed,” says Andy, “and it really comes down to the help of our volunteers. We can’t stress enough how invaluable they are to us. This garden was built on volunteers really, if they weren’t here, this would all be mud and I’d be lying somewhere over there exhausted.”
Once the plants in the garden have been protected for winter, the staff and volunteers will turn their attentions to the many projects that get pushed down the priority list in the busier seasons.  For instance, a section is being prepared for a new Somerset levels display.  So it would seem that not only is there always something to see in the Botanic Garden, there is inevitably always something to do – even once it’s been put to bed.

Autumn in a new light

Posted on by andy.winfield

     Some of my fondest memories of autumn are as a child holding my parent’s hands on a crisp afternoon, watching as my little red welly boots swished through the dried fallen leaves of the season. Even now as an adult, I can’t resist shuffling a little when conditions are right, just so I can watch the warm colours roll across my feet and listen to the rustle of autumn. However, last Friday Nick Wray, Curator for the Botanic Garden, opened my eyes to a whole new set of autumn delights – from winged bushes to exploding seed pods – this season is about so much more than just falling leaves.

Fruit and flowers
The small orange fruits of G. tinctoria

     The first stop on our tour was the plant Gunnera tinctoria, which to the untrained eye looks very much like rhubarb on steroids, and as a result is commonly called giant rhubarb. This species is smaller than the one commonly seen in British gardens, Gunnera manicata, but otherwise looks the same. As the plant prepares for its dormant winter phase, the large leaves have started to bend to the ground, revealing a world of colour beneath. Wrapped in a sheath of red feathery tufts are the promises of next year’s growth – buds, which will grow over the winter months ready for next spring. Beside these are the large influorescences, rising up like staffs from the base of the plant. Here, thousands of tiny orange fruits are housed, each one the product of a tiny pollinated flower.

     Growing on the north side of the house, in constant shade, is proof that autumn is still a time for flowers – Begonia grandis. This is a woodland plant from southern China and its pretty pink flowers are only one part of this plant’s colourful display. Turn the leaves over and an extraordinary cinnamon red is revealed.

Flower of B. grandis with the colourful dark underside
of the plant’s leaves in the background. 

“This is an evasion strategy,” Nick starts to tell me, “plants can’t get up and run away from predators, but they can masquerade as something else. Herbivores mooching about through the understory are likely to think there’s something wrong with this plant as the leaves make it look as though it’s dead or dying.”

Nick then takes me around the corner to one of his favourite plants in the garden, Impatiens tinctoria – a balsam. I can instantly see why it’s a favourite as the flower is truly stunning. Native to the mountains of western Ethiopa, this plant is adapted to cold dry winters and warm wet summers. The plant towers above me and Nick tells me all this growth has happened since the second week of May – an extremely fast growing plant indeed!
Flower of Impatiens tinctoria.  

     This plant has been producing flowers since July and they are clearly built for bee pollinators. A deep crimson runway guides the bee toward its nectar reward and as it enters the flower, its back rubs along the anther, dusting it in pollen. The pollinated flowers produce a rather extraordinary seed capsule, which is of course another important aspect of autumn….dispersing the next generation.

Scattering seeds
     Like all balsams, I. tinctoria has an explosive seed capsule. Each one is about 3cm long (just over an inch) and resembles a tiny cucumber. Water pressure keeps the capsule extended, but when a little force is applied, the sides of the capsule spring into their natural curled state of repose and the seeds are literally catapulted out. This explosive dispersal method is partly why Impatiens is very successful as a genus. However, this beauty is not to be confused with Impatiens glandulifera (Himalayan balsam), which was introduced as a garden ornamental by the Victorians and is now found choking many of the waterways throughout the UK.
The bladder-like fruits of Colutea arborescens

     Another wonderful example of autumn seed dispersal in the garden is the Bladder Senna, (Colutea arborescens). Though this plant doesn’t bring any colour to the garden at this time of year, the fruits offer their own element of intrigue. Native to the Middle East – Turkey, Iran, Iraq – the beige fruit resembles slightly deflated balloons dangling from the branches. Open it up, however, and inside you find two rows of perfectly paired little black seeds. As winter approaches, these fruits will fall off the tree and be carried across the dry land by the wind, much like tumbleweed. As the fruit tumbles along, it starts to tear and break down and the seeds get released. This type of seed distribution is very successful, particularly in the seasonally dry climates where it is found.

Losing leaves
     Besides the fruits, flowers and seeds, there is no denying that the Botanic Garden also offers a colourful display of leaves at this time of year. All the autumn colours are represented – yellows, oranges and even vibrant reds.
     As the days get shorter, many plants stop producing a type of plant hormone known as auxin. Among their many roles, auxins prevent a specialised layer of cells at the base of the leaf stalk – the abscission layer – from developing completely and cutting off the internal tubes that connect the leaf to the rest of the plant. So, once auxin levels drop, the abscission layer functionally cuts the leaf off from the rest of the plant. The chlorophyll, which gives the leaves their green colour, disintegrates rapidly revealing the other pigments carotene and anthocyanin, giving the leaves their autumn colours.
The bright orange seed of E. alatus seems dull compared
to the vibrant colour of the leaves

     Nick brings me over to Euonymus alatus, the colour of which almost hurts the eyes. The leaves are a fiery fuschia colour. This species is from China and it gets its name alatus, which means winged, from the hard sharp protrusions from the stem that protect the plant from herbivores. In the summer it’s a pleasant green shrub, but this time of year it is ablaze with colour. If the leaves weren’t enough, scattered throughout the bush are tiny fruits, which have split to reveal a single bright orange seed – a delicacy for birds.

     Other plants, such as the witch hazel, (Hamamelis mollis ‘Pallida’), don more golden hues but are no less spectacular.
H. mollis glowing gold against the evergreen backdrop
of Atriplex humilis (Fat Hen family)

     Nick had to run to a meeting, but I stayed in the garden for another half hour, taking photographs and crouching down to look at plants from new angles and examine parts that are usually hidden by lush foliage any other time of year. It was a whole new way to experience autumn. Of course, I still shuffled through the fallen leaves on my way out…some things are sacred.

Remember – next weekend (26th-28th October) is the 25th British Orchid congress at Writhlington School!