Autumn/Winter 2011/12 - Harcourt Arboretum - University of Oxford

Autumn/Winter 2011/12 

79 

The University of Oxford 

Botanic 

Garden 

News 

For friends and supporters 

of the University of Oxford 

Botanic Garden and 

Harcourt Arboretum 

Contents | A few words… | Invaluable volunteers | Recent developments 

Education update | The Bobarts Group | Visits and events for Friends 

Garden and Arboretum events | The last word

2 Botanic Garden News | No. 79 

A few words... 

Timothy Walker is Director of the Botanic Garden and 

Harcourt Arboretum; part of his job involves lecturing to 

undergraduates not only on plant lifecycles but also on 

control of invasive species. 

by 

Timothy 

Walker 

Is biology a science or was Lord Rutherford 

correct when he claimed “that which is not 

physics is stamp collecting” It seems harsh 

on the chemists but the boundary between 

physics and chemistry has always struck 

me as very fuzzy. The problem with biology 

is that it is rarely black and white, and 

particularly ecology and plant conservation. 

Whilst punting up the River Cherwell at the 

beginning of August the plants that I thought 

were duckweed (Lemna gibba) were actually 

a mixed community of Lemna and Azolla, 

known variously as mosquito fern, fairy fern, 

water fern or duckweed fern. Now you might 

think that a mat of this non-native species is a 

Bad Thing. But the truth is complicated. 

“Duckweed fern” is a good common name 

for use in countries that have duckweed. 

Elsewhere in the world Azolla is known as 

“Mosquito fern” derived from a belief, perhaps 

misplaced, that if the surface of a pond is 

covered with Azolla then the mozzies cannot 

lay their eggs in the water. The weed may 

indeed help to reduce the amount of oxygen 

available to the larvae and so help to control 

mosquitoes. A thick mat, however, will shade 

out any other plants in the pond and may 

result in the death of fish and invertebrates. 

“Water fern” is a good name because 

Azolla is a fern that floats on the surface of 

the water, but it is not the only floating fern. 

Another is Salvinia which is closely related 

and which has occasionally been placed 

in the same family as Azolla. The former, 

however, is not hardy at all whereas the latter 

will survive the British winter even though it 

is originally from tropical to warm temperate 

regions of America. 

The country of origin is perhaps irrelevant 

as Azolla has now spread throughout the 

world. It is not considered to be a true UK 

native species having been introduced as 

an ornamental in the 1840s. Its habitat is 

ponds or larger areas of standing water and 

it is not very salt tolerant. This summer may 

have been the coldest for twenty years but 

it has not been very wet and for much of it 

the Cherwell and its tributaries have been 

flowing very slowly. This, coupled with the 

absence of serious frosts in 2011, has meant 

that the Azolla has been very happy. 

Azolla has a deserved reputation as an 

invasive thug because it can grow very fast. 

It has been shown to double its weight in 

three days. Part of the reason for this is that 

inside its leaves are chambers containing 

colonies of a cyanobacteria, Anabaena 

azollae, which can fix atmospheric nitrogen. 

This puts the Azolla at a selective advantage 

over its neighbours because its growth is 

not limited by the amount of nitrogen in the 

water. The real limiting factor for this plant 

is phosphorous but not in English rivers into 

which fertiliser leaches. 

The ability of Azolla to fix nitrogen has 

been recognised and exploited by farmers in 

China for over a millennium. Azolla is grown 

in rice paddies around the plants and this 

helps to suppress the weeds in the fields. 

A mixed community of Azolla and Lemna 

After the crop is harvested and the water has 

drained away, the mat of nitrogen-rich Azolla 

can also be ploughed into the soil before the 

next crop. 

It has been calculated that Azolla can 

provide up to a tonne of nitrogen per acre 

per year. If you have Azolla growing on a 

pond in your garden it can be scooped out 

and used as a very good compost accelerator. 

Azolla is also thought to be a nutritious 

food for stock including chickens. If you 

have neither a compost heap nor chickens 

you may want to control the plant. A 

recently developed option is to exploit a 

herbivore that was probably introduced

Botanic Garden News | No. 79 

3 

into the UK unintentionally with plants 

before the 1920s. The tiny 2mm-long weevil 

Stenopelmus rufinasus has been here for 

decades and yet has found no other plants 

palatable. It is therefore now acceptable to 

release large numbers of the weevil even 

on Sites of Special Scientific Interest (SSSI). 

Using one introduced organism to control 

another is a risky business but in this case it 

seems to be safe. 

Azolla is odd. It is a fern, as already 

mentioned, but it does not produce clouds 

of spores from the underside of its leaves, as 

do bracken and the like. The floating green 

plants of Azolla produce a structure found in 

very few ferns – a sporocarp. This is a vessel 

which contains the sporangia that produce 

the spores. (The rusty pustules on the 

underside of terrestrial ferns are sporangia.) 

However Azolla, unlike most ferns, produces 

two types of sporangia, male and female, 

and so two different sporocarps. The female 

sporocarps are smaller but they contain 

just one sporangium which produces just 

one female spore. When conditions are 

right, the spore germinates and grows into 

the female gametophyte inside the spore 

but this then bursts through the spore wall 

Azolla on the River Cherwell in Oxford 

revealing several archegonia each with one 

egg. (In case it has slipped your mind, the 

gametophyte is a stage in the life of plants 

that has no equivalent in the life of animals 

and fungi. The gametophyte is responsible 

for producing gametes: sperm in antheridia 

and eggs in archegonia.) 

The male sporocarps are 2mm in 

diameter and contain many male sporangia 

which each produce many male spores 

which, despite being released from the male 

sporocarps, hang together in a mass called a 

massulae. The spores have a barb (a glochidium) 

and this also helps the group of spores 

hang on to a female spore that contains the 

female gametophyte. Inside each male spore 

a male gametophyte develops, upon which 

develops one antheridium that produces 

just eight sperm. These swim to the archegonium 

and fertilise the egg. The resulting cell, 

the zygote, divides and grows into the green 

Azolla plant and the life history is complete. 

Despite its current dubious reputation 

Azolla has a past that might make it important 

in the future. A long, long time ago in 

the Eocene, 55.8 to 37.2 million years ago, 

the continents were distributed differently 

from their current arrangement. In particular 

there was an ocean on the North Pole that 

was almost completely surrounded by land 

and thus cut off from the deep, global ocean 

currents. At this time, the Earth was so warm 

that the flora near the poles was what we 

now consider to be sub-tropical. 

The isolation of the Arctic Ocean and the 

high temperatures led to an odd, layered 

arrangement of the water in the ocean 

similar to that found in the Black Sea today. 

This consisted of a layer of relatively warm 

freshwater (from the rivers surrounding 

the Ocean) on top of colder and denser salt 

water. This was particularly so around the 

edge where the water was also enriched with 

minerals such as phosphorous washed in 

by the rivers. These were perfect conditions 

for Azolla, which grew like Topsy, taking up 

vast amounts of carbon dioxide. It has been 

calculated that over an 800,000 year period 

the Azolla, which covered up to four million 

square kilometres, caused an 80% drop in 

carbon dioxide levels from 3,500 ppm to 

650 ppm. 

As the Azolla died and sank in the waters 

its decay was halted and the carbon was not 

released. It was then even more securely 

locked away on the bed of the ocean in 

sedimentary layers. This huge decline in 

carbon dioxide levels started the chain of 

events that led to the present global climate 

with ice at the poles rather than palm trees. 

Perhaps this could be considered in the 

search for a method of sequestering and 

removing carbon dioxide today We think 

Azolla is an invasive thug, but perhaps it 

could be our saviour As I said at the beginning, 

biology is rarely black and white. 

Azolla with sporocarps

4 


Invaluable volunteers 

by Alison Foster, 

Mary Isaac and Tom Price 

“It was an enjoyable and relaxing 

experience, nice people to chat 

to and share garden stories with. 

Now I’m doing more volunteering. 

It’s not like weeding at home, the 

surroundings make it worthwhile!” 

Isabelle Kandler, weeder 

Victorious over the Nothoscordum: volunteers (l-r) Rose Holman, Ruth Sutherland, 

Sally Strang and Isabelle Kandler 

For several years the clamor from the Friends to get their hands dirty 

and volunteer in the Garden and Arboretum has been steadily growing. 

With the arrival of the new Senior Curator Alison Foster and Arboretum 

Curator Ben Jones in spring 2011, we started thinking about ways the Garden and 

Arboretum could welcome more volunteers. 2011 is designated the International 

Year of Volunteers, building on the success of the first IYV held in 2001, and 

in July PlantNetwork, the national network of botanic gardens, arboreta and 

other documented plant collections, organised a conference on Volunteers 

in Botanic Gardens and Arboreta. The timing was perfect as we at the Garden 

and Arboretum were keen to learn from others who had experience of the 

benefits and challenges of using volunteers. Alison, Ben and Mary Isaac, Friends’ 

volunteer co-ordinator, went to the conference, held at the University of Bath. 

We attended sessions on volunteer strategy and policy, employer-supported 

volunteering, volunteers and the law, and many other topics. We came away 

inspired and determined to make the most of the information we had gathered, 

and we are now starting to develop a long-awaited volunteer programme. 

Volunteer Keith Holmes planted hundreds 

of trees on Palmer’s Leys at the Arboretum 

Friends have been involved in volunteering 

since the beginning of the organisation 

twenty years ago and have helped in 

many ways: running the biennial plant 

sale, organising visits to gardens, doing 

administration and assisting at special events 

and at Friends’ coffee mornings. However, 

volunteer members of the Friends have, 

for many years, been requesting that they 

could be more ‘hands on’ at the Garden and 

Arboretum, and this year we have been given 

invaluable help by a series of keen volunteers 

from the Friends and elsewhere. Several 

projects have been on the go since spring 

2011, all of which have proved to be a huge 

success, benefiting both the Garden and the 

Arboretum, and the individuals involved. 

The first group of volunteers responded 

to our cry for help in dealing with 

Nothoscordum x borbonicum, a bulbous 

plant native to South America and the 

Garden’s worst pernicious weed. For 

decades Garden staff have struggled to keep 

on top of this. Various methods of control 

have been employed, including treatment 

with glyphosate, soil removal and even high 

voltage electrocution! However, nothing 

seems as effective as hand weeding. 

The first team of volunteers arrived at 

the Garden on a beautiful sunny morning in 

April 2011. A meet and greet ensued, so that 

we each knew who was who, followed by an 

induction to explain the problem at hand 

and how we planned to manage it. We spent 

the morning weeding the offending plant 

out of the vegetable beds. The team were 

amazed at its tenacity: how could it produce 

so many bulbs, be so tiny and such shades 

of brown as to be camouflaged against the 

soil The work required hand weeding and 

sifting of the soil, slowly working through 

each bed. 

This may sound neither interesting nor 

glamorous, but the volunteers involved 

really enjoyed doing it. They loved working 

in a team, being in the peace of the Botanic 

Garden, in beautiful surroundings and also 

found the task very satisfying. 

The same team returned fortnightly 

for three months to weed two beds in the 

Monocot quarter, where Nothoscordum was 

particularly prevalent. The first team then 

passed the baton to a second team who 

completed their three-month stint at the 

end of September. 

The impact on the Nothoscordum 

population has been huge. The teams 

have managed to eradicate completely the 

large parent bulbs from the beds and have 

significantly reduced the number of smaller, 

daughter bulbs. This means that there will be 

fewer bulbs of flowering age next spring, so 

less dead heading required to avoid seeding. 

“As a way to support the Garden, 

I can’t recommend volunteering 

highly enough and hope our 

experience will encourage other 

Friends to become involved in a 

hands-on way too.” 

Ruth Sutherland, weeder


5 

Nothoscordum bulbs 

If this project continues, we’re confident that 

we can bring the Nothoscordum population 

down to a manageable level and, hopefully, 

eradicate this menace completely in the 

longer term! 

Meanwhile, other volunteer projects at 

the Garden and the Arboretum have included 

weekly watering of newly planted material 

during the very dry spring; dead heading; 

dividing and potting up plants from the 

Herbaceous and Autumn Borders ready for 

the Friends’ plant sale next summer; planting 

bulbs; a volunteer gardener for the vegetable 

beds; volunteer involvement in clearing 

Rhododendron ponticum at the Arboretum; 

and data entry on our new plant records 

database. The Friends’ Administrator also has 

regular and invaluable administrative help 

from a volunteer member of the Friends. 

Without the help of these individuals we 

could not have maintained the collections to 

the level achieved this year, nor continued 

developing the Garden and Arboretum for 

the years ahead. It has been an absolute 

“Volunteering at the 

Botanic Garden is not 

only fun and rewarding 

but it gives me the 

opportunity to feel 

part of the team and to 

learn from the experts. 

It’s also great knowing 

you’re doing something 

to help and that all the 

vegetables that we’ve 

so lovingly grown go 

to people who really 

appreciate them.” 

Ness Newman, who has 

been volunteering half 

a day a week since July. 

She works on the vegetable 

beds with Jim Penny of 

the Hardy Team. 

pleasure to have enthusiastic and committed 

volunteers working with us and we 

would like to say a very big thank you to all 

our volunteers, past and present, for their 

hard work and positive influence on the 

Garden and Arboretum. 

We are now developing a bigger 

programme for volunteers at both the Garden 

and the Arboretum. There will be roles in 

maintenance of all sorts, both regular activities 

and one-off projects: planting, dividing, 

weeding, dead heading, potting, grass edging, 

leaf picking, watering, clearance work, plus 

data entry and library administration. And 

we still have lots of the ‘usual’ activities for 

Friends to help with – the Friends’ plant sale, 

special events, coffee mornings, garden visits, 

festivals and picnic days. 

If you or anyone you know would 

be interested in joining the volunteers, 

please contact us at: 

volunteers@obg.ox.ac.uk or by post to: 

Volunteers, Oxford Botanic Garden, 

Rose Lane OX1 4AZ. Thank you. 

A volunteer’s 

experience 

by Sally Strang 

When I replied to a request for weeders 

at the Botanic Garden I did wonder 

whether this was a rather rash decision. 

Did I really want to weed another patch 

when there was plenty to do in my own 

garden Three months seemed a long 

time to commit to, albeit for only a couple 

of hours every two weeks, and it wouldn’t 

be much fun if the weather was cold 

and wet. As it happened it was a magical 

spring - warm, sunny and dry. 

On our first morning our small group 

of volunteers was greeted warmly by 

Mary Isaac and Tom Price and after 

a short health and safety session we 

were introduced to the noxious weed 

whose rampage through the Garden 

was the reason for our recruitment. 

Nothoscordum had defied all attempts at 

eradication and it had been decided that, 

perhaps as a last resort, teams of weeders 

working methodically through the beds 

might slow down its progress. Tom 

explained carefully what was expected 

of us; he and his staff were always 

welcoming and were there to answer our 

questions, though at no time did we feel 

that someone was hovering over us. 

Each week we were shown where 

to weed and set to work at our own 

pace, chatting or comparing the size 

of a particularly fecund specimen or 

just taking in the tranquility of our 

surroundings. It was a pleasure watching 

the changes in the Garden through 

the spring. The birds sang, the bells in 

Magdalen Tower reminded us it was 

coffee time, inquisitive ducks investigated 

and groups of school children 

chattered past clutching their finds. We 

marveled at the blue of the irises and the 

smell of spring enveloped us. 

On each return visit we would eagerly 

scan the six foot’s worth of bed which 

we had weeded last time to see if any 

Nothoscordum had dared to reappear. 

On the whole the beds seemed reasonably 

clear and it will be interesting to see 

what happens next year. 

We all felt quite sad at the end of our 

term but enjoyed a picnic lunch with the 

garden staff and the lovely scones and 

jam which they produced for us. Everyone 

seemed to think that we had made a 

difference and were really grateful and on 

our part we felt that it had been a privilege 

to work in the Garden. I’m not sure what 

my motivations were but it was lovely 

to be more involved and to learn in the 

process. I would highly recommend it!

6 


Recent developments at the 

University of Oxford Botanic Garden 

and Harcourt Arboretum 

by 

Timothy 

Walker 

It is universally acknowledged that this has been a very good year for fruits. 

The possible reasons fall into two groups. Firstly, there was nothing to 

upset flowering and thus pollination of those flowers. Although December 

2010 was bitterly cold, in central Oxford we have escaped serious frost so far 

in 2011. The winter flowering plants were late but then spring was a bit early 

and spectacular. Secondly, the conditions through the summer may not have 

been good if you were camping, but if you were a plant growing and swelling 

fruits, they were perfect. 

The many and various fruits of the family 

Rosaceae are especially abundant this year. 

The flowers of the members of the Rosaceae 

are very easily recognised because in them 

it looks as if the stamens are growing from 

the base of sepals. In fact the stamens, 

sepals, and petals all grow around the edge 

of a cup-like structure called a hypanthium 

but the petals fall off before the other 

structures do. The hypanthium is in fact 

the fused bases of these three whorls 

of structures. However, the fruits of the 

members of the Rosaceae are very varied, 

in part due to the hypanthium and the 

receptacle that supports all the floral parts. 

The division of the species in the 

Rosaceae into genera has been controversial 

since John Ray (the 17th century English 

naturalist) was a lad and probably long 

before then. In particular it has been very 

difficult to see how the 950 species with 

pomes can be grouped. A pome is a fleshy, 

indehiscent (not opening at maturity along 

lines or pores) fruit, consisting of a modified 

floral tube surrounding a core, as in apples. 1 

The plants with pomes are not just 

apples but pears, quince, loquat, hawthorn, 

medlar, cotoneaster, sorbus and pyracantha. 

To quote a 2007 paper 2 there is “limited 

Sorbus 

sargentiana 

Sorbus domestica 

forma pyrifera 

Sorbus 

aria 

Sorbus 

latifolia 

Sorbus domestica 

forma pomifera 

Sorbus 

torminalis


7 

Rhododendron bashing at the Arboretum: (l-r) Director Timothy Walker, trainee Katie Benallick and horticulturalists Richard East and Jim Penny 

resolution of a complex evolutionary 

history”, or to put it another way, we don’t 

know what’s related to what. It is a classic 

example of Darwin’s lament that “we have 

no written pedigrees [so] we have to make 

out community of descent by resemblances of 

any kind.” 

The situation is complicated by the 

fact that these species don’t seem to know 

where the boundaries lie either, and form 

hybrids with species in quite different 

genera. 3 So for example at the Botanic 

Garden we have a hybrid between hawthorn 

and medlar (x Crataemespilus) and another 

between rowan and pear (x Sorbopyrus). It 

is further complicated by the fact that some 

species indulge in apomixis, where seeds 

are produced without the need for fertilisation, 

resulting in very localised variants. It 

appears that this is a group which evolved 

very quickly a long time ago, but since then 

there has been very slow divergence of their 

DNA. This divergence is very important for 

building classifications based on DNA. 

A wise old taxonomist once told me 

that “where there is confusion at the macro 

level there will be confusion at the molecular 

level” and in this case he was right. Confusion 

can be seen from the fact that in the 

1850 guide to the Botanic Garden, written 

by Professor Charles Daubeny, the applefruited 

form of the service tree is referred 

to as Pyrus domestica. In the 1914 guide 

written by Dr Gunther it is Pyrus sorbus. 

The current label says Sorbus domestica 

forma pomifera. Unfortunately this now 

needs to be changed to Cormus domestica as 

there is no evidence to support the grouping 

together of all of the species that were 

formerly in the genus Sorbus. 4 Interestingly, 

the genus had already been sub-divided 

into sub-genera (or sections) along similar 

lines. 5 If you want to see the differences for 

yourself, the Botanic Garden is a splendid 

place to do this. We have Sorbus domestica, 

S. torminalis, S. sargentiana, and S. latifolia 

inside the Garden and there are S. aria trees 

on the High Street outside. Our new orchard 

includes apple trees and other culinary 

species which are already starting to bear 

fruit. We also have Cydonia oblonga, Mespilus 

germanica, and many other species at 

both the Garden and the Arboretum and 

they are all doing very well this year. Many 

of their fruits also make terrific jelly. 

Not to be outdone the woody plants at 

the Arboretum have also fruited well. The 

squirrels have had a feast on the acorns 

which have formed carpets under their 

parent trees. 

Rhododendron ponticum is an important 

plant at the Arboretum but it can get carried 

away. This year, as every year, some of it 

has had to be coppiced and grubbed out to 

prevent it from swamping other plants. This 

also reduces the risk of invasive diseases, 

such as Phytopthora, spreading. 

Orchard planting at the Botanic Garden

8 


Recent developments at the University of Oxford 

Botanic Garden and Harcourt Arboretum 

The fruits of Magnolia campbellii ssp 

mollicomata have given a good show at the 

Garden. These rather unpleasant looking 

structures are a vivid cerise with erumpent 

orange seeds. Each seed is housed in a 

separate ovary which is easier to see at this 

time of year than in the spring when the 

plant is in flower. For the first time that I can 

remember, the Magnolia x soulangeana has 

also set fruit. 

Magnolia campbellii ssp mollicomata 

Back at the Garden the fruiting of the 

woody plants has been matched by the 

flowering not only on the Autumn Border 

but also on the big Herbaceous Border. At 

the beginning of September this was looking 

as good as it has all year, perhaps benefiting 

from the mild, wet summer. For many visitors 

the highlight of the Autumn Border has been 

not the dahlias but the salvias. In particular, 

Salvia oxyphora, which is a pink that you 

might think was incompatible with any 

other colours and yet it looks wonderful with 

Canna musifolia and Dahlia ‘Summer Night’. 

Two plants have excelled this year at 

producing scent in the evening. Whilst this 

is an unhelpful comment when the Garden 

closes at 5pm these are two plants which 

Friends might like to have at home. The first 

is Clerodendron trichotomum var. fargesii. We 

grow this against a west facing wall and it is 

very happy. The ivory coloured flowers are 

presumably pollinated by moths. A tender 

plant for a conservatory attached to the house 

is Murraya paniculata the scent of which 

is very similar to that of the Clerodendron 

outside. We grow it in a shady part of the 

Palm House. Whilst in this area it is worth 

mentioning a new flowering record for the 

Garden: for many years we have been nurturing 

a plant of Cubanola domingensis from 

the coffee family, the Rubiaceae. The flowers 

are extraordinary – tubular and pale yellow, 

they hang vertically downwards, and are 

more than eight inches long. We do not know 

yet what pollinates it but it is an amazing 

example of the apparent extravagant, almost 

wasteful, nature of biology. 

1 Harris & Harris (2001) Plant Identification 

Terminology. Spring Lake Publishing 

(a must-have book for a gardener interested 

in plant bits). 

2 Campbell CS et al (2007) “Phylogeny of sub 

tribe Pyrinae” Plant Systematics & Evolution, 

Vol 266, pp119-145. 

3 Robertson et al (1991) “A synopsis of genera 

in the Maloidae (Rosaceae)” Systematic 

Botany, Vol 16, pp376-394. 

4 Potter D et al (2007) “Phylogeny and classification 

of Rosaceae” Plant Systematics & 

Evolution, Vol 266, pp5-43. 

5 Bean WJ (1980) Trees and shrubs hardy in 

the British Isles, Vol 4, pp399-404. 

The herbaceous border at the Botanic Garden


9 

Education update 

by Lynn Daley and Sarah Lloyd 

We’re delighted to report that the Garden 

Primary Education Officer Emma Williams 

had a baby girl, Tegan, in September. We 

welcome Leah Whitcher who is covering 

Emma’s maternity leave. Leah is an 

environmental science and geography 

graduate who has worked as a marine ranger, 

a gardening journalist and a primary school 

teacher, specialising in art and outdoor 

education. 

We had a very busy summer with lots of 

events including, in July, Alice’s Day and a 

Forest Picnic Afternoon, both of which drew 

large crowds to the Garden to take part in a 

variety of activities. 

To celebrate 2011 as the International 

Year of Forests, we ran a series of family 

friendly events throughout August, each 

addressing a different aspect of trees and 

forestry. Though occasionally hampered by 

the British summer, these afternoons proved 

very popular. There was also a series of new 

trails at the Arboretum, which gave visitors 

the opportunity to discover different aspects 

of the site, on and off the more popular 

paths. Each week the trails were linked to 

the themes of the family friendly events – so, 

for example when the event was ‘Trees are 

Great for Exploring’, the related trail encouraged 

visitors to go ‘Around the World in 

Eighteen Trees’. 

Our ever-popular autumn programmes 

for primary schools began in early September 

and have, as usual, booked up very 

quickly, giving lots of children a chance see 

autumn colours and to create autumnal 

art works at both the Botanic Garden and 

Harcourt Arboretum. Half-term events for 

families included making autumn lanterns 

at the Arboretum and tie-dying at the 

Botanic Garden using natural dyes created 

from hedgerow plants. 

Leah Whitcher 

A-level chemistry students from three 

Oxfordshire schools came to the Botanic 

Garden and the University Department of 

Chemistry for a programme of free activities 

during the autumn term. They visited 

our Chemistry at the Garden exhibition (see 

page 13) and then went to the Department of 

Chemistry for a practical workshop in which 

they synthesised indigo. (Natural indigo is 

derived from the plant Indigofera tinctoria 

but the dye can also be synthesised in the 

laboratory.) 

In October we ran the first of a series of 

seasonal primary school teacher CPD (continuing 

personal development) courses at the 

Arboretum. The aim is to help teachers to 

make the most of the outdoors in their teaching. 

The Arboretum provided the perfect 

venue, with a variety of habitats and stunning 

autumn colour. The winter course will take 

place at the Botanic Garden in January and 

will provide teachers with ideas and practical 

advice as to how to incorporate outdoor activities 

at a time of year when many school groups 

huddle indoors and miss out on lots of handson 

learning opportunities. 

A badger shelter built by children as part of the den-building activity 

at the ‘Trees for Materials and Shelter’ afternoon at the Arboretum in August 

A-level chemistry students synthesise indigo

10 


The Bobarts Group 

giving extra support to the Garden and Arboretum 

by 

Jennie 

Turner 

The Bobarts Group, founded in 2004, is the 

Patrons’ group of the Friends. It gives those who 

wish to, the opportunity to contribute extra 

financial support to the Garden and Arboretum 

on a regular basis. Bobarts members enjoy all 

the benefits of being part of the Friends, plus 

a special programme of exclusive small group 

visits to private gardens. They are also invited 

to an annual reception at which they meet 

personally the Director, the Senior Curator 

of the Garden and the Curator of Harcourt 

Arboretum. 

Members join the Bobarts for a number 

of reasons: one describes it as the chance 

“to support the Garden and Arboretum and 

especially their education programmes and their 

conservation and commitment to plant diversity. 

The visits to private gardens in small groups, 

accompanied by people with similar interests in 

gardens and gardening, are particularly enjoyable. 

Such groups do not overwhelm even the 

smaller gardens and the owners are particularly 

welcoming and hospitable.” Many Bobarts have 

forged new friendships through their membership; 

others are simply happy to give extra 

financial support to the Garden and Arboretum. 

A brief account of the events that Bobarts 

members have enjoyed this year will give 

readers a flavour of the outstanding gardens 

we have been able to visit. Every year we are 

invited to an Oxford University department 

or college to see treasures of botanical art and 

herbaria hidden away in many of the city’s 

ancient buildings. This year we visited the 

University of Oxford Plant Sciences Department 

to see the original paintings and herbaria 

presented in the book Planting Paradise, a 

recent Bodleian publication whose author, 

Dr Stephen Harris, Druce Professor of Oxford 

University Herbaria, showed us the collection. 

His willingness to share his knowledge with us 

was wonderful. 

The 17th century barn, Campden House, Gloucestershire 

On a perfect spring day in May we visited 

The Old Rectory, Farnborough, an outstanding 

four acre garden with magnificent views, 

whose owner Mrs Caroline Todhunter showed 

us round. The deep parallel herbaceous borders 

were full of rare and interesting plants. The 

newly planted small arboretum with a number 

of rare Quercus trees and the Cornus kousa and 

the Davidia involucrata, both clothed in their 

spectacular bracts, were outstanding. 

Lord Carrington welcomed us to Bledlow 

Manor with its beautiful walled gardens, 

the famous Lyde Water Garden with paved 

parterres and a wonderful collection of 

contemporary sculptures. He walked around 

with us and was full of amusing and interesting 

stories of his time as Foreign Secretary. We 

then went for a delicious lunch at Mill Barn, 

the nearby home of Sir Richard and Lady 

Lapthorne, whose private garden was so exciting, 

with its individual rooms. They shared 

their passion for their garden with us. 

Kiftsgate Court is a magnificent four acre 

garden with spectacular views largely created 

by the grandmother of the present owner, 

Anne Chamber. The introductory talk to 

the garden, and then the walk around the 

twists and turns amongst the glorious roses, 

unusual plants and shrubs, were a delight. 

Later we visited Dean Farm, an ambitious 

and very successful garden surrounding a 

series of converted barns and including a 

courtyard garden, a sheltered walled garden 

with a distinctly Mediterranean theme, 

and woodland walks. We were told that the 

owner had to import 650 tonnes of topsoil to 

convert the very alkaline soil to the one that 

supports the present variety of plants. The 

coolness of this midsummer evening sent us 

inside for a drink in the owner’s warm kitchen 

and more stories about the creation of this 

very special garden. 

Sculpture 

at Radcot 

House 

Home Close is the private 2 acre garden 

of a Bobarts member designed with terraces, 

walls and hedges to divide the garden into 

ten distinct areas to reflect a Mediterranean 

interest with trees, shrubs and perennials, 

planted for all year effect. For once we could 

Bledlow Manor, Buckinghamshire 

enjoy the wine and delicious canapés outside 

in the evening sun before we all drove home 

in a deluge, such has been the mixed weather 

this summer. Radcot House is another very 

special exuberant new 2½ acre garden with 

sixteen large colourful beds. Calm areas of 

lawn are bisected by a canal and enclosed 

by high beech hedges. The extensive use of 

grasses, unusual perennials and interesting 

sculptural surprises was a good talking point 

as we moved around the garden. We went 

on to Campden House with its 1½ mile drive, 

set in fine parkland in a hidden valley with 

lakes and ponds. The wide walled terrace 

in front of the house, which was built in 

the 17th century and enlarged in the 19th, 

leads to a mixed border of interesting plants. 

The displays in the many pots were one of 

the most original aspects of the garden. We 

were very privileged to have our tea in the 

panelled dining room. 

Finally, the Bobarts Day this year was held 

at Harcourt Arboretum. The reception was 

followed by a tour with the Director Timothy 

Walker and Senior Curator Alison Foster, and 

even those of us who had visited many times 

learnt more about the trees and meadows 

than ever before. 

Membership of the Bobarts costs £140 

per annum for individuals and £225 for two 

people living at the same address. If you are 

interested in joining the group, please contact 

the Friends’ Administrator, Liz Woolley, on 

secretary@fobg.org, 01865 286690.


11 

Visits and events for 

Friends and their guests 

by Jane Annett, Harriet Bretherton and Pauline Coombes 

Please book using the accompanying 

booking form. Visits tend to get booked up 

fairly quickly so to avoid disappointment 

please send in your form as soon as 

possible. If you have any queries, contact 

the Friends’ Administrator, Liz Woolley, 

secretary@fobg.org, 01865 286690. 

Friends’ coffee mornings 

Fridays 2nd December, 3rd February, 

2nd March 

10.30am on the first Friday of every 

month (except January and August) in 

the Garden’s Conservatory. After coffee a 

member of staff leads a tour of the Garden. 

≠≠ 

No fee and no booking required, 

just turn up 

Sunday plant tours at the 

Botanic Garden 

Sundays 13th November, 22nd January 

and 25th March, 10.00am until 11.30am 

These tours are with the Director Timothy 

Walker and are structured around plants 

of particular interest for the time of year. 

They are crammed with botanical 

information and horticultural tips and 

are great fun. A plant list is provided. 

≠≠ 

Friends £2, guests £6 

(includes entry to the Garden) 

≠≠ 

No booking required, just turn up 

Garden visits 

We have had another successful summer 

and autumn of wonderful trips to very 

special gardens. Thank you for your 

continued support, we do hope you have 

enjoyed the visits and we always welcome 

feedback and suggestions for future events. 

Next spring Friends are invited to the 

following gardens: 

Worcester College, Oxford 

Friday 10th February 2012, 2.00pm 

Worcester College, Walton Street, 

Oxford OX1 2HB 

Colesbourne Gardens 

Friday 19th February 2012, 11.00am 

Colesbourne Park, Nr Cheltenham, 

Glos GL53 9NP 

By kind permission of Sir Henry and Lady Elwes 

The tour will take the group through the 

gardens to see both the massed display 

of snowdrops in the wild garden and the 

collection of rarer cultivars in more formal 

surroundings. There are also masses of 

Cyclamen coum, Eranthis hyemalis, and of 

other plants of winter interest. There will 

be an introductory talk on the history of 

Colesbourne and the Elwes family and the 

background to the diversity of snowdrops. 

Coffee will be served. 

≠≠ 

Tickets £15, guests £20 

≠≠ 

Maximum 50 people 

Stone House Garden 

Saturday 25th February 2012, 2.00pm 

Wyck Rissington, Cheltenham, 

Glos GL54 2PN 

By kind permission of Mr & Mrs Andrew Lukas 

This garden, created over the last twenty 

years, is one for all seasons, with an 

emphasis on strong structure and good 

foliage. There is a bulb flowering every 

month of the year, even in a frost pocket 

on heavy clay. Specialist hellebores appear 

in December and the meadow starts with 

crocus in early January; by April it is awash 

with fritillaries. Tea will be served. 

≠≠ 

Tickets £10 , guests £15 

≠≠ 

Maximum 50 people 

Tours of the 2012 Olympic 

Games sites in London 

Saturday 17th March and 

Friday 23rd March 2012 

Coach departing from 

Water Eaton Park & Ride, Oxford, 

at 8.00am, back at c. 7.00pm 

Tours led by Blue Badge Guide Mr Ian Gibson 

This is a departure from our normal garden 

visits, but we thought that it would be a 

good way for us to see the Olympic sites 

and to hear what has been achieved in 

preparation for this historic event. The 

tours will start at the Tower of London 

after a coffee. We will go to Docklands, 

Canary Wharf and the Thames Barrier. We 

will have lunch/picnic at Greenwich Park 

and then see a number of venues including 

the Olympic park velodrome. There will 

be an afternoon stop for tea at the Olympic 

village. Our guide is very entertaining and 

knowledgeable and will show us some of 

the new landscaping and gardens. Some 

walking involved. 

≠≠ 

≠≠ 

Tickets £30, guests £35 (includes 

coach fare but not refreshments) 

Maximum 50 people each trip 

As part of the Garden’s Public Education 

Programme there will be a lecture by Prof 

James Hitchmough on the development 

of the wildflower meadows at the Olympic 

Park, on 22nd March at the Said Business 

School in Oxford (see page 14). To book visit: 

www.oxforduniversitystores.co.uk or use 

the form at the back of the Public Education 

Programme leaflet. 

By kind permission of The Garden Master 

The garden is known for its summer 

displays, but the winter is an excellent 

time to see its structure as well as 

picturesque views and magnificent trees 

and shrubs. The College has a collection of 

snowdrops and early bulbs which should 

be in flower at the time of the tour. We 

will be shown around by a member of 

the gardening team who will talk about 

the history of the garden, the gardening 

techniques used, and plans for the future. 

Tea will be served. 

≠≠ 

Tickets £10, guests £15 

≠≠ 

Maximum 40 people

12 


Double visit to Iford Manor, 

Lower Westwood, Bradfordon-Avon 

and Derry Nursery 

of Special Plants 

Saturday 14th April 2012 

Coach departing 9.00am from Redbridge 

Park & Ride, Oxford; back at c. 4.30pm 

Iford Manor by kind permission of 

Mrs Elizabeth Cartwright Hignett 

This Grade I Italianate garden was designed 

between 1899 and the 1930s by the architect 

and landscape gardener Harold Peto. It is a 

unique romantic hillside garden characterised 

by steps, terraces, sculptures, cloisters and 

magnificent rural views. The current owners 

have restored the layout and planting to 

Peto’s original designs. Coffee will be served 

on arrival. Picnic or pub lunch in Bradfordon-Avon. 

In the afternoon we will visit Derry 

Nursery of Special Plants to have a tour, buy 

from the wide selection of unusual plants, 

and have tea. 

≠ Tickets £30, guests £35 

(includes coach fare) 

≠ Maximum 50 people 

The University of Oxford 


Sunday 22nd April 2012, 2.30pm 

Nuneham Courtenay, Oxon OX44 9PX 

By kind permission of Mr Ben Jones, Curator 

A chance to see the magnificent bluebells 

and to meet Ben and hear about plans for the 

Arboretum. The tour will be followed by tea. 


Ros Diamond 

Friends’ seed 

collection 

We will have a limited number of 

packets of seeds to give away in early 

January. Each packet will contain a 

mixture of annuals, biennials and 

hardy perennials, collected from the 

Botanic Garden. To receive your free 

seeds, please send an SAE (at least 

postcard-sized, and as soon as you 

like) to: Friends’ Seed Collection, 

Oxford Botanic Garden, Rose Lane, 

Oxford OX1 4AZ. 

Rousham House 

and Garden 

Thursday 3rd May, 2.00pm 

Rousham House, near Steeple Aston, 

Oxon OX25 4QU 

By kind permission of Mr & Mrs Charles 

Cottrell-Dormer 

This is a great opportunity to visit this 

wonderful house at Rousham and to 

have a guided tour of the garden with 

the landscape archaeologist James Bond, 

whose interest is in the development of 

the English landscape garden. The house 

was built in 1635 and has remained in 

the ownership of the same family ever 

since. It was extended by William Kent 

in the 1740s, who also designed the 

garden. It is one of the finest examples 

of the first stage of the evolution of the 

English landscape garden and is the 

best-preserved survivor of a William 

Kent design. We will have a picnic tea 

under the Seven Arches in the garden. 


≠ Maximum 40 people 

Summer dates 

for your diary 

The Friends’ plant sale 

Sunday 3rd June 2012 

Harcourt Arboretum, Nuneham 

Courtenay, Oxon OX44 9PX 

Our planning for the 2012 plant sale is 

well under way and with the completion 

of the new car park at the Arboretum we 

hope it will be another great success. 

We will be selling an enormous range 

and variety of plant stock from the very 

rare to the more common, including trees, 

perennials, annuals, exotics, grasses, 

shrubs and kitchen garden plants. We will 

also have a useful stall selling secondhand 

gardening and cookery books, an 

advice table, a great garden-themed raffle, 

fabulous refreshments with homemade 

cakes, jams and goodies and lots of parking. 

Admission is free and you will be able to 

explore the Arboretum and see the glorious 

late spring displays of trees and flowers, 

before or after buying plants (which can be 

delivered by wheel-barrow to your car). 

All the plants for the sale come from the 

Botanic Garden, college gardens, private 

collections and members of the Friends. 

If you are dividing plants this autumn 

please remember us and add a few extra 

to be sold in June in support of the work 

of the Garden and Arboretum. For this 

sale we hope to increase our range of vegetables, 

fruit and herbs, so we will particularly 

welcome any donations of excess stock 

which you may have. To make this event 

a success we need many, many plant 

donations so if you would like to help please 

do contact me at any time. Thank you. 

Maura Allen - 01865 311711, 

0777 212 7029 or mea@armitstead.com 

New College Opera 

Wednesday 11th July 2012 

Following the success of Salieri’s Falstaff 

in 2011, we are delighted to announce that 

New Chamber Opera will be performing 

Mozart’s Il Re Pastore in July 2012. Attendees 

described 2011’s event as: “a truly excellent 

evening” and “a magical evening”. Further 

details and ticket prices for 2012 will appear 

in the next newsletter in early March.


13 

Garden and 

Arboretum events 

The Public Education 

Programme 

The Garden and Arboretum’s 2011/12 Public 

Education Programme is now well under 

way. Tickets are still available for many 

events, including the following lectures 

and courses: 

Undergraduates from the Department of Chemistry who helped to design 

the Chemistry at the Garden exhibition 

Chemistry at the Garden 

Open daily during normal Garden opening 

hours; continues until early January 2012. 

The Botanic Garden is hosting a special 

exhibition to celebrate 2011 as the 

International Year of Chemistry. Research 

scientists at the University of Oxford 

Department of Chemistry have designed 

posters and self-guided activities to 

encourage an interest in plant-based 

chemistry, to increase the appreciation of 

chemistry in meeting world needs, and to 

generate enthusiasm for the creative future 

of chemistry. 

≠≠ 

No charge other than for Garden entry 

A change of 

name... 

At the Friends’ AGM in October it was 

agreed to update the Friends’ official 

name from ‘The Friends of Oxford 

Botanic Garden’ to ‘The Friends of 

Oxford Botanic Garden and Harcourt 

Arboretum’. The Friends have supported 

the Arboretum for many years and we 

feel that it is appropriate to reflect this 

in our name. The change also supports 

the growing emphasis that Garden 

and Arboretum staff place on working 

collaboratively across the two sites. 

Family friendly events 

at the Garden 

Our naturally-decorated Christmas tree, 

a firm favourite with children and adults 

alike, will be on display in the Conservatory 

from late November. 

Big Botanic Christmas Tree 

Saturday 3rd December, 10.30am-12.30pm 

Make natural decorations from seeds, leaves 

and pods. Take some home and leave some 

hanging on our tree. 

≠≠ 

No need to book, just drop in; no 

charge other than for Garden entry 

Fairtrade Fortnight 

Monday 27th February – Sunday 11th March 

2012, during normal opening hours 

Explore the tropical glasshouses, looking for 

plants that are grown around the world as 

Fairtrade crops. 

≠≠ 

No need to book, just drop in; no 

charge other than for Garden entry 

International year 

of forests lecture 

Tony Kirkham 

Trees – A cut above the rest 

Thursday 24th November, 8.00pm 

The talk covers various subjects relating to 

the growing of trees in cultivation. It will 

remind the audience of where trees come 

from, the threats that they face today both 

in their natural habitats and in cultivation 

and how we must use this knowledge to 

help us understand cultivation techniques 

such as planting and pruning and keeping 

trees stress free. 

≠≠ 

Said Business School, Oxford 

≠≠ 

Tickets £12 

We apologise for the fact that some 

Friends may not have received 

the Public Education Programme 

leaflet. You can view the leaflet’s 

contents on -line at: www.botanicgarden.ox.ac.uk/Education/obgeducation-public-1.html 

or, if you 

would like to be sent a paper copy, 

please contact: secretary@fobg.org, 

01865 286690.

14 

Winter lecture series: 

Gardens around 

the world 

With the Olympics in mind,this special series 

of lectures brings together leading gardeners 

and garden designers to give us their 

perspectives on gardening around the world. 

≠≠ 

≠≠ 


Lectures take place at 8.00pm 

in the Nelson Mandela Auditorium 

at the Said Business School in Oxford 

Tickets cost £12 per lecture (includes 

a glass of wine) or £54 for the series 

of 5 lectures 

Dan Pearson 

A garden for a thousand years 

Thursday 26th January 2012 

The 240 hectare Tokachi Millennium 

Forest on Hokkaido, the northernmost 

island of Japan, is the brainchild of the 

media entrepreneur Mitsushige Hayashi, 

who acquired the land with a view to 

offsetting the carbon footprint of his national 

newspaper business, Tokachi Mainichi. 

In this talk Dan Pearson will describe the 

genesis of the Millennium Forest project, 

his involvement in the creation of the 

masterplan, and the challenges faced in 

creating large scale massed perennial 

plantings and a monumental sculptural 

landform environment. 

James Wong 

The gardens of Singapore 

Thursday 9th February 2012 

A unique, contemporary blend of East and 

West, the tiny ‘Garden City’ of Singapore is 

fast becoming a global centre for innovation 

in tropical horticulture and landscape 

design. James Wong will guide us through 

the city state’s distinctive emerging garden 

design style, from its origins as a vital 

outpost for the introduction of new plants 

across the British empire, to its new multibillion 

dollar ‘space age’ botanic gardens by 

the Bay. 

Elizabeth Banks 

Gardening is happiness – 

window boxes to the 

President of the RHS 

Thursday 23rd February 2012 

Join us to hear how a passion for plants 

led Elizabeth Banks from her own garden 

to her current role as President of the 

UK’s leading gardening charity, the Royal 

Horticultural Society. 

Isabelle van Groeningen 

The Royal Garden Academy 

in Berlin: The revival of 

German horticulture 

Thursday 8th March 2012 

In 2008 Gabriella Pape and Isabelle Van 

Groeningen re-opened the former Royal 

Gardeners Training Institute in Berlin. 

Europe’s oldest surviving horticultural 

training establishment has a new lease 

of life, and is the foundation for a new 

German Horticultural Society. 

Prof James Hitchmough 

Meadows at the Olympic park: 

elysium in the east end 

Thursday 22nd March 2012 

The London Olympic Park includes very 

large-scale native wildflower meadows, 

rather more cosmopolitan creations of 

South African Drakensberg grasslands and a 

North American prairie, in gardens that wrap 

around the Olympic Stadium. Join James 

Hitchmough to hear how and why these areas 

were conceived and designed, the process by 

which they were established on the ground, 

and the role of his research over the past 15 

years in minimising the risk of failure. 

Practical horticulture 

study mornings at the 


≠≠ 

≠≠ 

≠≠ 

Led by members of the 

horticultural team 

Study mornings take place between 

10.30am and 1.00pm except Successful 

staking which begins at 11.00am and 

finishes at 12.30pm 

Tickets cost £20 per session 

Successful staking 

Tuesday 6th March or 

Wednesday 7th March 2012 

Learn the skills of staking with the horticultural 

staff as they stake the herbaceous plants at the 

Garden using natural materials harvested from 

the Arboretum coppice. 

Plant propagation 

Tuesday 13th March 2012 

This session will include the hows, 

whys and wheres of propagation, what 

equipment to choose and use, appropriate 

selection of materials, techniques, practical 

demonstrations and aftercare. 

Citrus care 


Come along to learn how to cultivate and care 

for citrus plants. Topics covered in this session 

include the selection of species and cultivars, 

year-round requirements, potting, feeding, 

pruning, pests and diseases of citrus. 

Cacti and succulents 


You don’t have to have a vast glasshouse to 

grow cacti and succulents successfully. Come 

along to find out which species are good for 

indoor cultivation, what their year-round 

requirements are, how to repot them, what 

and when to feed them and what pests and 

diseases may affect your plants.


15 

Botanical illustration 

courses at the 


Rosemary Wise, who has been the Botanical 

Illustrator for the University of Oxford since 

1965, will lead these courses. Come along to 

benefit from her expertise and experience 

in the beautiful surroundings of the Botanic 

Garden. 

≠ 10.00am to 4.00pm 

≠ Tickets cost £60 

(includes a sandwich lunch) 

Botanical illustration 

for beginners 

Saturday 17th March 2012 

Botanical illustration - 

intermediate and advanced 

Saturday 21st January 2012 

Botanical course at 


Meadow plants 

identification day 

Tuesday 29th May 2012 

Led by the Director, Timothy Walker, this 

day-long course will teach you basic plant 

identification skills and give you the chance 

to try these out on the meadow flora in the 

beautiful setting of Harcourt Arboretum. 

≠ 10.00am to 4.00pm 

≠ Tickets cost £60 


Practical course at 


Creating a wild flower 

meadow 

Wednesday 6th June 2012 

Join Charles Flowers for this course 

looking at the process of establishing 

a wildflower meadow. The day will 

include an illustrated talk and an 

outdoor session looking at Palmer’s 

Leys, our newly restored meadow. 

Topics covered will include buying or 

collecting seed, propagating, the effect 

of soil type and pH, seedbed preparation, 

sowing and managing. 

≠ 10.00am to 4.00pm 

≠ Tickets are £60 


Please book on-line at www.oxforduniversitystores.co.uk, or by completing the booking form in the printed Public 

Education Programme leaflet. If you would like us to send you a leaflet, please contact secretary@fobg.org, 01865 286690. 

Introduce a new 

member to the 

Friends and earn 

yourself a thank you! 

Introduce a family member, friend 

or colleague to the Friends of Oxford 

Botanic Garden and Harcourt 

Arboretum and we will send you a 

£5 voucher for each new member 

you introduce, to be redeemed 

against tickets for Friends’ events 

and visits or the Garden’s Public 

Education Programme. 

There’s no maximum number – 

for every new member you introduce, 

we will send you a £5 voucher. 

Enter your name and membership 

number in this form, cut it out and 

give it to the new Friend to complete 

and return to us; then we’ll send you 

your voucher. Vouchers must be 

redeemed within 12 months of the 

date of issue. 

When complete, please 

send this form to: 

The Secretary, Friends of 

Oxford Botanic Garden, 

Rose Lane, Oxford OX1 4AZ, 

secretary@fobg.org, 

01865 286690. 

Your details (the Friend introducing a new Friend) 

Name 

Membership category 

Annual single membership @ £28 p.a. 

Single life membership @ £560 

Bobarts Group single membership @ £140 p.a. 

1 Joint membership is open to two people living at the same address 

Membership number (on your membership card) 

Details of the new Friend(s) 

I wish to become a member of the Friends of Oxford Botanic Garden in the category indicated. 

Title Given name Surname 

Title & name of second member (if any) 

Address 

Post town 

Email address 

Telephone 

(please tick) I can be contacted by email about membership, ticket or other queries. 

Postcode 

(please tick) I would like to receive copies of Botanic Garden News by email (three times a year). 

(please tick) I would like to receive occasional extra news updates by email. 

Payment of annual membership fees 

It is very helpful to the Friends if annual membership fees are paid by Direct Debit. 

You will receive an initial 15 months’ membership for the price of 12 if you pay by Direct Debit. 

Please send me a Direct Debit mandate; or 

I enclose a cheque for £ ________ (payable to The Friends of Oxford Botanic Garden) 

Gift Aid 

Please sign and date below if you are a UK tax payer. This will allow the Friends 

to recover tax amounting to 25% of your subscription at absolutely no cost to yourself. 

I wish the Friends of Oxford Botanic Garden to reclaim tax on all subscriptions and donations I have made to 

the organisation in the last four years. I confirm that I pay Income Tax or Capital Gains Tax at least equal to the 

amount of tax which will be reclaimed on my subscription or on any donation. 

Signed 

Annual joint 1 membership @ £45 p.a. 

Joint 1 life membership @ £900 

Bobarts Group joint 1 membership @ £225 p.a. 

Date

16 


The last word 

by 

Timothy 

Walker 

F 

erns such as Azolla that are featured 

in this edition’s “A few words” may 

be an ancient group of land plants 

with an illustrious past but they are 

new kids on the block compared with their 

nitrogen-fixing cyanobacteria lodgers. The 

cyanobacteria belong to a very ancient lineage 

of living organisms that have had an even 

more profound influence on the Earth and its 

biology than has Azolla. 

Cyanobacteria, also known as blue-green 

algae or blue-green bacteria, have been 

described as “arguably the most successful 

organisms on Earth”. This claim can be 

Gunnera leaves in the Bog Garden cut and laid down to protect the rhizomes over winter 

supported by the fact that they are found in 

almost every habitat from seasonally dry, 

bare rocks in cold regions to hot springs 

where life should not exist. Moreover, fossil 

cyanobacteria have been dated at more than 

3,000 million years old. Part of their success 

has to be due to their ability to photosynthesise 

and fix atmospheric nitrogen. It is 

believed that their photosynthesis has made 

a significant contribution to current oxygen 

levels in the atmosphere. 

You might wonder why gardeners should 

be interested in these little organisms. 

The answer is simple: about 1,200 million 

years ago one of these photosynthesising 

cyanobacteria was engulfed by another 

single celled organism but rather than being 

digested and broken down, the cyanobacteria 

remained intact and was press ganged 

into a symbiosis. This cell was the first plant 

and had this endosymbiotic event not 

happened our gardens would be empty. 

Another species of nitrogen fixing cyanobacteria, 

Nostoc punciforme, lives in the vast 

leaves of Gunnera manicata which has grown 

bigger this year than anyone can remember. 

It is one of those odd quirks of biology that 

the tiny leaves of Azolla and the huge leaves 

of Gunnera both contain cyanobacteria. 

Perhaps cyanobacteria could be introduced 

into crop plants to replace the need for 

nitrogenous fertilizers 


November to February: 

open daily 9.00am to 4.30pm, 

last admission 4.15pm 

March, April, September & October: 



May to August: 



We are closed on Christmas Day 

and Good Friday 

No dogs allowed in the Garden 

(except assistance dogs) 


Rose Lane, Oxford OX1 4AZ 

Tel: 01865 286690 

E-mail: postmaster@obg.ox.ac.uk 

Web: www.botanic-garden.ox.ac.uk/ 

Garden/obg-intro.html 

University of Oxford Harcourt Arboretum 

December to March: 

open Monday to Friday 10.00am to 4.00pm, 

last admission 3.30pm; closed weekends 

April to November: 



We are closed 22nd December to 3rd January 

No dogs allowed in the Arboretum 

(except assistance dogs) 

University of Oxford Harcourt Arboretum 

Nuneham Courtenay OX44 9PX 

Tel: 01865 343501 

E-mail: postmaster@obg.ox.ac.uk 


Harcourt/obg-harcourt-intro.html 

The Friends of Oxford Botanic Garden 

and Harcourt Arboretum 

Rose Lane, Oxford OX1 4AZ 

All Friends’ enquiries, including those about 

Friends’ events, should be made to Liz 

Woolley, the Friends’ Administrator 

Tel: 01865 286690 

E-mail: secretary@fobg.org 


Friends 

Please note that the Friends’ office is staffed 

only on Tuesdays and Wednesdays, between 

9.00am and 4.00pm. At other times urgent 

Friends’ enquiries will be dealt with by 

Garden staff. 

The newsletter is published by the University of Oxford Botanic Garden and is edited by Liz Woolley 

and Timothy Walker. The views expressed in articles are those of the authors and do not necessarily 

reflect the policy or views of the Visitors of the Botanic Garden. 

Design by Richard Boxall Design Associates

Autumn/Winter 2011/12 - Harcourt Arboretum - University of Oxford

Create successful ePaper yourself

Delete template?

Save as template?