Braving the elements (in more ways than one)

As gardeners we are all used to dealing with "the elements"on a daily basis - braving whatever the weather throws at us. Never has this been more true than this year. However, at the University of Oxford Botanic Garden we are a positive lot and thought we'd embrace "the elements" - but in a different way altogether.

Following on from a successful collaboration with our colleagues in the Department of Chemistry (the other "Elements") in 2011 to celebrate International Year of Chemistry, we have teamed up once again to deliver a new audio trail entitled "Chemistry at the Garden" which is available free of charge to all our visitors. During the summer, a group of enthusiastic science communicators got together to record the audio trail on location at the Garden. Helped by the very patient Josh from the University podcast team, we told the stories of how plants have provided inspiration for chemistry research both in the past and still today.

The audio trail leads you around the Garden, where, at the appropriate places you trigger the sound by pointing the nib of the audio pen on a specially designed map. You can hear about photosynthesis, how the lotus plant has inspired the development of new materials, what makes the wonderful caramel smell that is wafting across the Botanic Garden on sunny days at this time of year and how the plants at the Garden helped an Oxford chemist win a Nobel prize.
Each of the trail stops lasts just a few minutes and gives you an insight into what motivates the research chemists to pursue their work.

The new audio trail was launched on the 13th September. The weather was kind and all those who came had fun exploring the collections with the audio trail. 

Another fantastic group who have braved "the elements" over the spring and summer are the volunteers who have been working at the Garden alongside our team of botanical horticulturalists. This year we have welcomed almost thirty gardeners and weeders who have enabled us to tame the weeds in the face of one of the wettest summers on record. Their help has been invaluable in keeping our worst weed (Nothoscordum) under control and their never ending enthusiasm to eradicate this beast is much appreciated. On Wednesday this week we said a proper thank you to all our volunteers (whether office based or practical, Garden or Arboretum) as well as all those who have given their time to support the Friends of the Botanic Garden and Harcourt Arboretum over the past year. This occasion was marked  of course by tea and cake (and more cake).

After consuming our bodyweight in cake we finished with a walk around the Botanic Garden, led by Gardens curator Tom Price.

It seemed only appropriate that is was pouring with rain!

Keys at the Sea

The Botanic Garden is a living collection of plants and, like any museum collection, it is important to know exactly what we are looking at. Plants can be identified in a number of ways- often it is enough to see a plant once and be told what it is to establish familiarity for life. Often it is possible to match the living plant to a picture or photograph in a guide. An image search on the internet, however, may provide us with a variety of plants from widely different families, all sharing the same name. It is obvious that identification has to come from an authoritative source. Luckily for botanists and gardeners this source exists in the form of comprehensive floras of native and garden plants. It was to gain experience in using these guides that staff from the Garden team attended a recent course in identifying coastal plants run by the Field Studies Council.

Saltmarsh at Shingle Street, Suffolk

Which Salicornia is which? 

The course took place in Suffolk under the expert tuition of Ros Bennett. Staff from the Botanic Garden joined other students in an effort to identify various coastal plants, mainly using the key from Stace's New Flora of the British Isles. A key of this kind lets the user choose between two descriptions of a plant. The chosen description will lead to another pair of descriptions, and so on, until the plant has been identified to the level of family, genus or species. Often the key features in these descriptions require a hand lens to be visible. The curious naturalist discovers a hidden world of microscopic beauty. 

Many beautiful plants grow in the ever-changing landscape of the salt marshes and shingle. Obviously, many are adapted to the high levels of salt and the regularly inundated mud of estuaries. While these plants may be impossible to grow in Oxford some, such as Sea Lavender (Limonium) and Sea Kale (Crambe maritima) are thriving in the garden.

In any case, learning how to use a flora allows us to identify plants from any habitat and encourages to look at the wonderful variety of detail that makes every plant species unique.

Keeping it in the family...

Towards the end of summer there is one plant family above all others that provides the final foray of colour, the daisy family: Asteraceae.

There are c. 27,000 species in this family assigned to 1,765 genera, making it one of the largest plant families. The diversity of this group is pretty staggering, with representatives found worldwide, only absent from the Antarctic mainland.  From annual herbs and arctic alpines to the narrowly endemic and threatened, arborescent Dendroceris of Chile.

We represent a reasonable amount of this diversity at the Botanic Garden, both in the Glasshouses and the Gardens. Here are a few:

Rudbeckia maxima

Rudbeckia maxima from the central and southern USA is a fine garden plant. It grows to about 1.8m, has sumptuous, glaucous, ornamental leaves and does not need staking. Grown as a repeated element through plantings it provides a very natural effect.

Dahlia 'Moonfire'

The Dahlias are now in full bloom, somewhat delayed by the weather. We cultivate a large number of cultivars at the Garden, mostly within the Autumn   Border. These are bedded out each June, following on from the spring flowering tulips and forget-me-nots. They are then lifted in late October and the tubers protected over winter in deep frames in the nursery. The best of the bunch include: 'David Howard', 'Moonfire' (right), 'Grenadier', 'Twinings White Chocolate' and 'Dovegrove'.

Bartlettina sordida

The Glasshouses hold a range of interesting species. Including the spiny shrub Barnedesia caryophylla from South America, Bartlettena sordida (left) from Mexico, which is vaguely reminiscent of Eupatorium and the endangered Centaurea akamantis from Cyprus.

Centaurea akamantis

As well as all these striking ornamental members of the family, it's also worth mentioning that many of them are familiar and important food crops. Both kinds of artichoke, Jerusalem (Helianthus tuberosus) and Globe (Cynara cardunculus var. scolymus) are in this family. The former has edible tubers containing inulin, broken down by bacteria in our large intestines yielding the familiar and rather antisocial side effects of eating these tubers!

Globe artichoke

Pop into the Botanic Garden over the next few weeks to see this family at its best.

Plotting on...

This year's curious weather has not been too kind to the vegetable plot. Unseasonal warmth and drought followed by months of cold rain... Most vegetables are annuals or are at least grown as such, and they need good conditions to establish themselves. Bad weather at the wrong moment can set crops back to the extent that they never really establish well. Perennials, on the other hand, can endure difficult conditions and even thrive in them- our rhubarb is a good example.

Courgette and sweetcorn bulking up.

Broccoli 'Beaumont'

Nevertheless, the vegetable plots  are producing. Last week the first brassicas were ready: cauliflower, calabrese and 'Hispi' cabbage were all harvested by Oxford Food Bank as part of their weekly collection. Courgettes, which had refused to grow in the cooler temperatures, finally began to bear fruit and the first french beans developed from the subtle pink flowers of 'Cobra'.

         Climbing French Bean 'Cobra'
   

It has been exciting to watch the onions bulking up since the days began to shorten after the summer solstice. This decrease in daylight length is the trigger for seed-grown onions to put all their growth into bulb formation. We sowed pinches of onion seed in modules at the beginning of february and planted out the whole modules. As they have grown the onions have just pushed each other apart. The drooping, yellowing tops are a sign that they will soon be ready to harvest!

Onion 'Ailsa Craig'

We have had to wait longer than expected for the potatoes to reach a worthwhile size- 'British Queen' is a second early and 'Anya' is grown as a maincrop, we get good results from harvesting it earlier and although the potatoes are smaller we can usually harvest before blight affects the plants. This year the humid conditions have caused some blight- in an attempt to save the crop we have removed all the foliage to ground level to avoid spores being washed off the foliage into the ground. So far, so good...

'British Queen' before losing her foliage to blight.

Giant water lilies, scarab beetles and sublime aquatics..

The Lily Tank in the Lily House is burgeoning and looking suitably exotic this week. The star of the show is the giant water lily, Victoria cruziana, which is in flower for the second time this year. This plant hails from South America and produces enormous floating leaves up to to 2.5m across. We grow it as an annual plant, sowing the pea-sized seeds in February and then plant out in the Lily Tank in April. The flowers open at night (or late in the day), each one lasting only two days. 

Victoria cruziana

On the first night of opening the flower is a pure white, this attracts the scarab beetle pollinator (Cylocephata castaneal) in the wild. At this point the female organs of the flower are receptive to pollen, but the flower's own male organs are not yet active. On the second night the flower changes to a pink-plum colour. At this stage the female organs are no longer receptive, but the male anthers are shedding pollen in abundance. In the wild the night flying beetle enters the flower on the first night, feeds on nectar through the day and then escapes on the second night covered in pollen. The beetle then visits another white flower promoting cross pollination.

Noah Walker at 10 weeks

There are many stories telling of floating young children on these leaves, we thought an experiment was required to test the theories. Back in 2001 new born Noah Walker, son of our Director Timothy Walker, was happily floated on one of the Victoria leaves. This made headline news in the Oxford Mail and prompted renewed interest in this tropical behemoth.

Noah Walker, August 2008

Some seven years later the question "just how much weight can a leaf support" was posed. Once again Noah willingly found himself the guinea pig. On a warm August day in 2008 Noah was again successfully floated on the leaf of Victoria.
Not wanting to stop there, Jonah, Noah's older brother, volunteered his services. Unfortunately on this occasion Jonah sank. So, in conclusion, the optimum load bearing capacity is somewhere between the weight of a seven and nine year old.

Nymphaea x daubenyana

Other plants of interest in the Lily Tank include Nymphaea x daubenyana, a hybrid that arose in this tank in 1874 and named in honour of Professor Charles Daubeny, a previous keeper of the Botanic Garden who installed the tank in 1851. Oryza sativa, cultivated rice, is grown along the margins, a plant that sustains 50% of the World's population as a staple food crop. A large stand of papyrus reed, Cyperus papyrus, occupies one corner of the tank. This is the plant used by the ancient Egyptians to manufacture papyrus parchment paper. Once common along the River Nile, it is now largely absent due to competition from invasive species.

Oryza sativa

Come down to the Botanic Garden and take a look for yourself. If you are in luck you might catch Victoria in flower.

Olympic aspirations...

James inspecting germination

In November 2011 Professor James Hitchmough arrived at the Botanic Garden to conduct the first of the sowings on the new Merton Borders. This week he returned to check on the progress.


We contacted James in early 2011, hoping that he would be interested in working with the Botanic Garden to establish sustainable plantings within the framework of Kim Wilkie's master plan for the Lower Garden. Much to our excitement James was eager to be involved. The timing could not have been better, with James designing and implementing schemes to wow the global audience at the Olympic Park this summer.


James visited the Garden and discussed his ideas, a concept followed along with a design. It was all very exciting and new, a great direction for the Botanic Garden to be taking. Our aim was to communicate alternative approaches to gardening, with the emphasis on sustainable development.

Eremurus stenophyllus

James' research focuses on producing highly ornamental, yet sustainable, naturalist plantings, based on the study of natural plant communities in the wild through the direct sowing of seed.

Seasonally dry grassland communities from three bio-geographic regions of the world are represented in the planting at the Botanic Garden:

Agapanthus 'Headbourne Hybrids'

• The Central and Southern Plains of the USA
• High altitude areas of Eastern South Africa
• Southern Europe to Turkey and across Asia to Southern Siberia

Once established the new borders will be transformed into a sustainable, dry (non-irrigated), highly ornamental planting. Our aim is to showcase plants that will become more important in the future if climate change models prove to be accurate. Over 100 species make up the planting palette, 85% of which are being established by the direct sowing of seed.

Oenothera macrocarpa var. incana

The seasons have been challenging, but seed has germinated well and we are now seeing the first flowering. James is confident that the display next year will be fantastic, and in a year or two can perhaps rival his plantings at the Olympic Park.


The Botanic Garden would like to thank the The Finnis Scott Foundation and The Monument Trust for making this project a possibility.


Drop by and take a look, new plants are coming into flower on a daily basis.

Engaging with our community...

On the 18th and 20th of July the Botanic Garden hosted picnic events for two local charities, Donnington Doorstep family centre and The Mill. 


The Botanic Garden cultivates a wide range of fruit and vegetables, which are harvested by volunteers working for the Oxford Food Bank. The produce is then donated to local charities in Oxford, ensuring fresh, locally produced food goes to those who need it most.

The charities were invited along to tour the Botanic Garden, harvest some veg and then make lunch using the produce freshly picked from our plots. There were also a number of craft activities to get involved with, all with a food related theme.

Great fun was had by all, both staff and participants. We very much hope to build on the success of these picnics and continue to work more closely with the charities involved.


A big thank you to all those who got involved, especially HLF trainee Vicki Wood who planned and delivered outreach sessions and organised both picnic events at the Garden.