Talks 2022-2023 membership year

Fen Ditton Gardening Club 15^th November

It was heartening to gather together on a November evening, even if it had been unseasonably mild, and be beseeched not to be too tidy, to leave the dead heads and the fallen leaves in the garden. Our speaker was Sharka Baxter, an energetic and persuasive lady from the Czech Republic who has lived and gardened in this country for many years. Sharka is both a garden designer and a gardening coach and her passion is to produce beautiful gardens which are sustainable for wildlife. Her talk, The Forward-Looking Gardener, aimed to get us all to think about what kind of garden we would like to achieve, and to keep that firmly in mind as we worked.

In previous years, the fashion in gardens was to tidy the grass, rake up leaves and cut down dead heads in the autumn but this destroys many homes for over wintering insects. In the spring and summer, we were encouraged to use a range of pesticides to rid our plants of any remaining insects and use fertilisers to promote plant growth. The result of this regime has been that the insect population has declined by 60% in the last 20 years, according to Dave Goulson, Professor of Biology at the University of Sussex. The biomass, the amazing amount of biological material which makes our soils so rich, has decreased also. Insects are the food source of many birds. They are the pollinators on which our food and many new medicines depend; without insects our plant production would be severely challenged. The biomass of the soil gives it the nutrients and the structure, the fertility and the richness for plant growth.

Sharka went on to discuss ways to help, by compost making and mulching, by planting native and naturalised plants among the beautiful imports we prize, by creating a pond, however shallow, by creating a meadow or at least leaving the grass long. In these ways, habitats and food sources suitable for insects are formed. When in the vegetable garden, use compost with no peat, use a regime which requires no digging and use no pesticides, insecticides or synthetic fertilisers. Her slides illustrated the gardens she had created using these principles, full of beauty and full of insect and bird life.

During the winter, composting can provide homes for many helpful creatures – and is easily carried out with a 50:50 mixture of cardboard and grass cuttings mixed with kitchen waste during the summer. Plants such as forget-me-nots self-seed and change the look of the garden year by year. Use such plants as sorbus for their pink or yellow berries to enhance the colour of the winter garden as well as provide food for birds. Allow borders to rest until March; leaves and even windfall apples can be used as a mulch. In spring, blossom becomes important and the advice is to plant as many bulbs as possible to provide colour. As the months progress, cow parsley, ragwort, tufted vetch, teasels and comfrey provide a show in a meadow area; roses and verbena, lavender and cosmos with alliums provide structure to fill the borders with colour and interest.

By autumn, many plants have formed seed; Sharka advises leaving the plants to die down in their own way, leaving the dead heads, leaving the scattered leaves and leaving the windfall fruit on the borders, providing both a mulch and organic matter for the next growing season but also homes for over-wintering insects. The insects will provide food for hungry birds and animals such as hedgehogs. To ensure that plants bought into your garden are disease free, Sharka advised only to source them from a trusted garden centre, or to beg cuttings and seeds from friends, and to beware of plants that have been ’treated’ to alter their growing conditions as they may not come back true to form in a second year. One last piece of advice which might be difficult to fulfil when the rains or snows of December and January are here, was that a newly planted tree needs to be watered throughout the winter and through the next 12 months.

It was an interesting and thought-provoking presentation and by the end, we were sure that we too could produce rich borders of colour whilst attracting birds, bees and butterflies.

FD Gardening Club Meeting on 17^th January 2023

What better time of the year, when most of the day is too dark and cold to enjoy lengthy forays into the garden, to begin to plan for the Spring! On the third Tuesday in January, a good turn out of members came together to listen to the advice of John Marshall, who has designed private gardens for many local people, commercial gardens such as the centenary garden at the Wesley Church in Cambridge and a medal-winning show garden for Hampton Court.

John and his wife reminded us that spring is just around the corner by arriving with a jug overflowing with winter flowering honeysuckle and daffodils and then proceeded to actively engage us, encouraging us to take notes and ask questions, as he described principles of good garden design along with descriptions of gardens he knew and where he had worked. He started by saying that we could just let our gardens happen or we could plan, by measuring and using graph paper and working out a strategy to get a pleasing picture from any angle, but keeping our budget and energy in mind and our ideas realistic.

A garden, said John, should be practical, functional and beautiful, with straight lines replaced by curves as far as possible, but the whole garden should not be on show all at once, as leaving hidden corners will excite the imagination. Often we have high fences to contend with, but these can be covered with trellis, or lowered a little and then height added with trellis for an assortment of climbers and sweet peas to clamber over. Keeping wildlife in mind, he recommended using native plants and shrubs such as pyracantha and cotoneaster which afford a good food source as well as places of safety for birds.

When deciding to plant a tree for its foliage or flowers, he asked us to consider the height and spread of branches as well as how it is to blend with other surrounding trees. Paths need to be at least a metre wide to accommodate wheelbarrows, pushchairs and wheelchairs and it is better to use gravel rather than pea shingle to try to prevent much movement. Edges need to be prepared properly with metal or wooden edging before the path is laid.

A plan needs to create a garden with a sense of space using sweeping curves for lawns and paths and allowing some parts to remain hidden round a corner or behind a hedge so there is the illusion that a path continues and there is more to discover. Different zones where the washing, the swings or sitting in sun or shade can be incorporated; those features you don’t want to see can be hidden using shrubs and climbers. A place to sit and eat needs to have easy access to the kitchen and a place to read needs solitude. Many people like to hear running water but whether a still pond or a fountain is what you have in mind, the best idea is to keep it simple.

Borders need to be least two metres wide and given differing depths using curved edges. An odd number such as a group of three plants, using a mix of annuals and perennials, provides a better planting arrangement than single plants. Space needs to be allowed for the trees and shrubs. With a thoughtful plan, vegetables and flowers can be mixed as long as the vegetables are planted out in the open and not under a hedge. Large pots, glazed inside to last, are also better in groups of three each filled with a generous planting mix. Herbs in such large pots can provide colour and be useful but need thorough watering.

I am sure the gardens of Fen Ditton will now be planned for all year round colour and interest, with cauliflowers and candytuft, mint and marigolds and hidden corners. I look forward to seeing the result. To thank John for his interesting and thought provoking talk, the Garden Club have made a donation to the Ripple Effect to help gardeners across rural Africa.

Fen Ditton Gardening Club 21^st February

In February, it seemed as though winter might give way to Spring with mild days and a sun which gave a little warmth although shady parts of the garden were likely to be still frost bound. A group of Gardening Club members met to listen to a chemist give her version of plants found in the garden and by the wayside. Gwenda Kyd’s academic research in Edinburgh kindled her interest in the chemical compounds manufactured within plant cells and she started studying plant based medicine, first as a hobby and now professionally. You may have met her taking a group of people round the Botanic Garden and she has brought out her second book discussing some of the plants to be found there.

Gwenda introduced her talk by pointing out that plant materials have been used for thousands of years to make cloth and medicines but it is in the last 50 years that about half of all drugs used have come directly or indirectly from natural sources. Often a drug used widely now is the same or similar to the drug used in traditional medicine.

One example is the use of willow bark, known to the Egyptians three and a half thousand years ago. In the early eighteenth century, the Reverend Ed Stone from Chipping Norton found that chewing the bark relieved his symptoms of the ague. His experimentation led him to isolate a white powder which we now know as salicylic acid, the active ingredient. Although continued use of this does produce unwanted side effects, the molecule can be adapted easily to become just as efficacious but without causing harm to other regions of the body and so acetyl salicylic acid or aspirin was produced. A hundred years ago, this was the effective drug against Spanish flu and, although other drugs have superseded it for aches and pains, it is still important and used widely in the treatment of stroke and heart attack.

A Shropshire physician was instrumental in using foxgloves as an aid to treating dropsy, the build-up of fluid in the soft tissue of the body; the active ingredient extracted from foxgloves is digitalis which has the effect of slowing and strengthening the heart beat. Foxgloves are known to be poisonous and in a medicine, a low therapeutic index (a measurement of the safety of a drug) is necessary - in this case, there is a very small margin for error. Digitoxin, a compound which can be isolated from digitalis, is still used for congestive heart failure although readers of Agatha Christie will know that foxglove leaves amongst the salad can be an effective murder weapon.

As is common knowledge, garlic is effective in protecting against witchcraft and particularly good at warding off vampires. Pasteur used it instead as an effective antiseptic. The two active chemicals react together when the plant cell walls are broken and the product is an antibacterial not only in humans but also in trees. It is extremely effective in killing horse chestnut canker although the strong aroma from the sulfur compounds may prevent its widespread use. In humans, garlic compounds are believed to thin the blood and reduce cholesterol and are effective against colon cancer.

A chemical found in conkers as well as the leaves, bark and flowers of horse chestnut trees is used to treat varicose veins; the active ingredient is escin, which is probably anti-inflammatory and may protect the cell walls. It ca n be taken as pills or as creams. Conkers are also supposed to stop spiders from entering homes but that is unverified.

The hallucinogenic compounds contained in henbane were prized by the ancient Egyptians. Scopolamine, the active ingredient, depresses the central nervous system and so can be used as an anaesthetic but has also been used by the CIA as a truth drug. It was the discovery of henbane in his wife’s body parts coupled with the newly invented telegraph that ended Dr Crippen’s dash for freedom in 1910. Scopolamine from Angel’s Trumpets is also implicated in date rape. However, it can be used in oral medicine to control children’s spasms and is a fast acting anti-depressant.

Those of you who like nothing better than listening to your music on vinyl will, I am sure, be aware of the fine hairs of the prickly pear which are excellent for using as gramophone needles. The pads themselves attract water and other nutrients, making prickly pears an excellent fencing material with the added advantage of providing a nutritional drink and one that is particularly tasty when candied. The pads also provide living space for scale insects, in particular the females of the cochineal beetles, which can be scraped off and pulverised into the red dye carmine for colouring cakes and clothing. The active ingredient is carminic acid. The chemicals inside the pads attract water so effectively that they can be used as a flocculating agent to remove bacteria and heavy metals from water and can even be used as an effective dispersant for oil spills.

We rely so heavily on plants to provide our food and our medicines but also to satisfy a host of other needs. It is apparent that it is in our interests to foster the greatest biodiversity possible and care for all plants around us as we never know just when we might need them. Gwenda provided us with much food for thought in an interesting and stimulating talk.

Fen Ditton Gardening Club - Tuesday 21^st March Dr Tim Sparks - Rewilding

The Gardening Club meeting in March was a meeting with a difference. Instead of discussions of the best onions to plant or how to protect Spring flowering shrubs from frost, Dr Tim Sparks gave a presentation on a re-wilding project in which he has been deeply involved. Dr Sparks’ background is in statistics and the interpretation of data, working in both agricultural and ecological research; his particular interests are associated with conservation and climate change and he aimed to give us enough knowledge to understand what re-wilding is all about.

Re-wilding is a bit like Marmite – you either love the idea or you hate it. About sixty years ago, research projects were set up in a handful of sites around the country to monitor changes to the landscape after the World War, and the effect of the growing use of pesticides such as DDT and heavy metals such as Mercury. An excellent site on Lake Windermere monitored the effects on fisheries; Monks Wood was set up to monitor the effects on ancient woodland. The research building itself was utilitarian and built over two years, including the harsh winter of 1962 – 63; it is set in a deciduous woodland in a county which is the least wooded in the country. Part of the reason for this lack of woodland is the huge population growth in the last two hundred years as better medicine and nutritional health has enabled people to live longer, but associated pressures came from agricultural requirements. Also, a lack of woodland management, as energy needs were switched from wood use to coal, meant that woods became neglected. The huge inland lake, Whittlesea Mere, remained undrained – until coal could provide the necessary energy to drive the pumps, and all that area then was able to be taken into farming.

The fragments of ancient managed woodland are well known locally – Hayley Wood and Waresley Wood have been much studied; these were traditionally managed by coppicing with more people employed per acre than in any other type of industry, as wood was needed for cooking, building and heating. Orchards such as those at Willingham, which provided fruit for the Histon jam factory, have long been grubbed up. Monks Wood itself used to straddle the A1 and, as the largest Ancient Woodland, covered an area of 150 acres as a National Nature Reserve. The landscape is changing and Dr Sparks work is to monitor how it is changing.

There are two areas under investigation, one where the grass has been allowed to naturally regenerate since 1996 and the other a north facing slope, which had been ploughed up to 1961, but then left as it was found to be unsuitable for arable farming. The former had been a grass field; a grid of posts 20 metres apart was inserted to aid regular monitoring, and it was found that four years into the monitoring, the grass sward was thick and deep with some hawthorne and dog rose appearing as well as lady’s smock, indicating the wet nature of the earth. After ten years, with wooden posts replaced by metal ones, the meadow was more like a wood with glades and dense hawthorn patches. The open nature of this landscape then began to fill; hawthorne, blackthorn, dog rose and bramble first appeared, these preventing the deer from grazing new saplings. This prickly ground cover has allowed the saplings to mature to 5 m, well above the nurturing hawthorne; the increased shade from field maple and ash eventually kills the ground cover as the vegetation changes to canopy. Bramble first increased and then decreased and oak is now increasing. After 23 years, there are still glades.

The older wilderness was originally a barley field, ploughed and then abandoned. Originally there was no grid and a party of Dutch students organised one. Some oak trees were noted early on but it was some 16 years after the start of the monitoring, that it was recorded that some hawthorne had taken root and trees were beginning to fill the gaps. Although it has been a problem to monitor in the same way as the younger meadow, the land is now wooded and, at 60 years, is a lovely wooded area with a pond. Individual trees are monitored – picked by being a metre in girth. Trees fall, nothing is cleared and the dogrose thickets get thinner as the canopy matures. Although the stinging nettles remain, the dogrose and blackthorn disappear as dog’s mercury, a plant indicating a long established undisturbed site, gains a root hold. As the canopy increases, small trees no longer survive but the heights of standing ash and oak increase. In 1947, there was a pond in an arable field; by 1991, it was hard to distinguish the pond. There are now 83% of common wild flower species found there but none of the rare species. There are as yet no bluebells or primroses, although these are found in Monks Wood itself.

The method of seed dispersal is important to explain where trees may become established. Oaks are spread right across the sites by jays and pigeons planting the acorns in disturbed soil. Ash and field maple rely on wind dispersal so are found round the site edges. Anything with fleshy fruits eaten by the birds will be wide spread.

Dr Sparks’ enthusiasm for this important subject of re-wilding was apparent in his presentation and the many questions afterwards showed an equal interest from members and guests in the audience. He described vividly what happens when Nature is allowed to take its natural course. How we then use that information is up to us.

Judy Potter

Fen Ditton Gardening Club 18^th April

I am writing this article on a day when the Royal Horticultural Society has exhorted us to love our dandelions and thistles. It seems, therefore, so appropriate that Dr Tim Bedford came to talk to the Gardening Club about Garden Bugs and whether we should cohabit with them, actively conserve them or just control them.

Dr Bedford’s passion for invertebrates started many years ago on the South Downs when, as a child, he started observing and collecting moths and butterflies. He was shown by a family friend how to use a bright light with a white sheet to attract night flying moths and then realised how much enjoyment was to be had by collecting and taking them home to nurture them, observing the stages of their reproductive cycle and eventually being able to release the newly emerged caterpillars back to the wild. Later in life, he furthered this interest by collecting pieces of amber which had inside them an imprisoned insect and was able to show to the Club a photograph of a moth which had been trapped in this way 80 million years ago; that moth shows nearly identical markings to a moth found today.

Joining the entomology unit at the John Innes Plant Science Research Institute, Dr Bedford studied aphids and the viruses they carry with them in their saliva. As the aphids suck juices from a plant, the viruses may cross over into the plant material. In particular, he researched into a fly and the associated virus that attacks Casava, a staple food of parts of Africa. A similar fly was attacking the tomatoes grown in polytunnels in the South of Spain, but here so much pesticide was being used in an attempt to control it that the tomatoes had to be rejected for human consumption. A new approach was needed and this came in a range of measures including nets, a wasp which ate the flies and soap based products which interfered with the waxy coating on the fly but are otherwise harmless to consumers. These, along with a strict regime of eradication of deadly nightshade plants, which also host the same flies, from both polytunnels and environs led to much improved control.

This problem illustrates the difficulty facing farmers and market gardeners, as aphids reproduce extremely quickly and so effective methods of control which are safe both for consumers and the environment are required.

One of the most interesting parts of Dr Bedford’s presentation was not about an insect but about a mollusc to which I have had an extreme aversion since I was a very small child – the slug. This gastropod has a bad press for chewing its way through our salads before we get a chance to do the same but apparently we are misguided, misinformed and mistreating them. Most slugs, especially the large ones, eat decaying vegetable matter and are an important part of the recycling process. Only the small Black Garden Slug and the Grey Field Slug carry out the damaging foraging we see in the garden and these do need to be picked off by hand. If they have become a real problem, Dr Bedford suggested putting down some old carpet or wet cardboard overnight – and then lifting it in the morning and collecting those molluscs hiding underneath. [Any offers welcome!] The message is that slugs are a Good Thing (mostly)!

To deal with snails, Dr Bedford recommended leaving out an old pot with shards of old clay pot inside. These nocturnal feeders will crawl in to hide during the day and can be safely removed to a part of the garden where little damage can be done – or left to feed any hungry thrushes.

The UK is the worst country in the developed world for biodiversity and so we do need to accustom ourselves to much less killing – less pesticide, less insecticide, less herbicide – so that bugs and molluscs can flourish and become part of the food chain and our gardens will once more thrill us with birdsong. Dr Bedford mentioned pyrethrins which are natural products and therefore allowed to be used by organic growers; pyrethrins are broad based natural insecticides and so, whilst they will effectively kill that carrot fly that has been ruining your crop, they will also remove many other harmless insects such as lacewings, ladybirds, bees and wasps, which have been busy pollinating in the rest of the garden, working hard as a necessary part of the ecosystem. If you have to use a pesticide, make sure it is species-specific, although it would be much better if, instead, you can use a deterrent such as a soap based product or pheromones which can attract specific insects to traps.

Patience seems to be important; waking up to hundreds of large, herbivorous Spanish slugs devouring his plants, Dr Bedford noted how difficult these molluscs were for birds and other predators to eat. They are larger and much slimier than their English counterparts and it was the sliminess that predators found difficult to deal with. Their numbers increased at an alarming rate – until the birds discovered how to wipe off the slime before enjoying their tasty treat and so decreased the numbers of slimy slugs until they are no longer the threat they had been.

The harlequin ladybug, when first seen on our shores, was thought to be an enormous risk to our own delicate little 7-spot variety but now the two seem to have settled into a happy coexistence; the harlequin’s speciality is to tackle tree aphids leaving the 7-spot to remove the aphids from the roses. Many other invertebrates aid us in defending our plants – the larvae of lacewings, centipedes, ground beetles, wasps and spiders all have their role to play and the message from Dr Bedford was to control rather than remove, to co-exist rather than to behave as supreme.

Overall it is important to identify your pest and then consider how best to tackle it. Decide whether it is control, co-habitation or conservation that you need and don’t forget that a small amount of harm might be accommodated alongside a great deal of good for the garden and for the environment.