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GALLS.
Aileen Stocks
This
is an old word that has several uses; all the definitions however,
include irritating' in their descriptions and the galls found in
plants are manifestations caused by an irritant.
Galls appear in many forms but all are the result of a plant's own unnatural growth in response to an irritant caused by a parasitic attack, This, for example, can be a fungus, insect, bacterium, eelworm or other invader. This does not include external infestations such as caterpillars as these will not provoke positive growth by the plant. Practically all plant families are affected by their specific parasites. Grasses. honeysuckles, knapweeds, viburnums, ground ivy, thyme, Euphorbia for instance and many trees including willow and ash, oak, aspen and poplar
An easy example found on trees is the 'oak-apple' - a gall found on the twigs of the oak tree. This is the plant's answer to eggs of Biorhiza pallida being laid in the base of a bud. It is spongy in June and July but later, after the adults have emerged through small holes, it dries and hardens and may persist all winter looking rather like a Malteser. The whole life cycle of this parasite is very complex and continues under ground at one stage in the rootlets of the tree. At one time these and other 'marble' galls were collected and used to make ink. There is not enough tannic acid in British galls for good results, though Aleppo galls apparently have far more. Once it was used for tanning and medicinally as an astringent. Oak Apple Day - May 29th - commemorates the Restoration of the Monarchy, with Charles II.
Another parasite to afflict the oak is a gall-wasp called Neuroterus quercuscaccarum. This gives rise to the showers of 'spangles', containing the larvae, in late summer, which cover the ground under the tree and, incidentally, provide food for some birds.
One very pretty gall, seen mostly on wild roses, is the 'Robin's pincushion' caused by the gall-wasp Diplolepis rosae. The eggs are laid in spring in unopened buds and the moss-like ball that follows is particularly colourful by September when it is bright rose. Known by country folk for hundreds of years it was used at one time to make bedeguar tea, allegedly, a cure for cattle diarrhoea.
Witches' brooms are easily seen in the bare, winter branches of birch and hornbeam, being the trees' response to parasitic attack by certain fungi.
Sometimes
plants grow in a peculiar form known as 'fasciation'. Forsythia,
jasmine, Hibiscus, Euphorbia, holly, Cornus,
Cotoneaster and even marigolds can all produce strange
malformed leaves and stems, galled by bacteria or other parasites.
The dreaded 'Hollyhock-rust' is caused by a fungus and can occur on many plants of the Malvaceae such as Malva, Lavatera, Abutilon and Sidalcea. Heavy infestation can result in distorted growth. First recorded from Chile in 1852 it appeared in Spain in 1869 and in England in 1873 and is now world-wide. As a general rule, as with most parasites, the host is only partially affected and rarely fatally. Ornamental trees and shrubs can be pruned if too disfigured and herbaceous plants rooted out if necessary. But there are a few galls that need closer attention. Gall mites can be serious pests if they infest buds of black-currants. spreading the causal agent responsible for the condition known to gardeners as "big bud'. The next stage is reversion and poor cropping. Burning affected plants and replanting in new ground with reputable stock is the only answer to this condition.
Clubroot is common and will affect all crucifers. This includes vegetables such as sprouts, swedes, and turnips, as well as flowers like stocks and wallflowers. The spores can survive in the soil, without hosts, for many years and it is very difficult to eradicate.
Taphrina deformans or Peach Leaf Curl is common and can vary from year to year. Light infestation might not do a lot of harm but repeated, heavy attacks will sap the tree's vigour and productivity.
There appears to be a gall for most, if not all, plants; some a colourful red like those caused by the sawflies on willows, some, the crown galls, almost unnoticeable if underground and the dramatic, arboreal outline of witches' broom. They have all been with us for a very long time and, no doubt, will continue to decorate our flora in the years to come.
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GARDEN WILDLIFE – RESIDENTS AND VISITORS
Joan Gunson 1997
I have always been interested in wild flowers and to some extent this led me into growing herbaceous plants, many of which are native wild plants or forms of them, as Bob Brown explained in his interesting talk to our Group last year. If we grow this type of plant as opposed to the very highly bred type, we will find that all other aspects of wildlife are attracted too, and what would a garden be without birdsong, the humming of insects or the added flash of colour of a butterfly's wing?
One of my favourite sounds is the chorus of croaking frogs on the first warm day in March; I have counted forty or more in the pond during this frenzied mating season. They also live in my polytunnels as uninvited, but welcome guests, as does Mr Toad, usually only spotted if I move a flower-pot from a dark corner where he will crawl away to find another resting place. Frogs are far more lively when disturbed, leaping around all over the place. We usually find both frog and toad spawn on the pond, the toad spawn being laid in a long ribbon which usually stretches from one side to the other. Newts too have occasionally been spotted, though I have not seen them recently.
Birds are, on the whole, (except for herons, stealing our fish), very welcome and mostly beneficial to the garden too. I have watched bluetits, while feeding their young, strip a rose-bush of aphids in a few hours. Thrushes, though scarcer nowadays, (I blame slug-pellets), still nest in our garden and get through a large number of snails in a season, choosing specific places to smash the shells open. Blackbirds seem to be the dominant bird these days but are none the less welcome – they consume lots of pests and who would want to be without their wonderful fluting song? As I write this now in January on a bitterly cold day, I can hear them practising in short bursts, like an orchestra tuning up. Linnets, greenfinches, and goldfinches also nest in our garden; though not primarily insect-eaters they do take some, but mainly feed on the many seed-heads we have throughout the year. It is quite a delight to watch a party of goldfinches feeding, fluttering around like overgrown yellow and black butterflies. Fieldfares and redwings are shy birds and will only come into our garden to feed in severe weather; last week a large holly tree, still covered in masses of berries, was stripped just in a day.
Insects too play an important role in our gardens, though I admit not all of them; one of the best loved and most beneficial is that aphid-eating beetle, the ladybird, of which there are over forty British species. So why are we so repulsed at those large black ground-beetles? Many have beautiful metallic-like bodies with a fluorescent sheen, and are useful scavengers. Even the much maligned wasp has its uses: I have often seen it visit flowers to sip the nectar, especially those that are darkmaroon or brown-coloured, such as Veratrum nigrum, Geranium sinense, and our native figwort, thus pollinating these plants.
If you have a pond or water nearby you may have been lucky enough to haves seen dragonflies this year; they are my favourite insect and I can never resist watching them. If they fly close enough, you can hear the whirring of their large wings; they are powerful fliers and have two distinct ways of hunting their prey, the hawkers patrol up and down a stretch of water, while the darters choose a favourite perch from which they repeatedly dart. Either way they consume a large number of pests such as midges and mosquitoes.
It has been a really good year for butterflies too. There was a large influx of the beautiful migrant Painted Lady, joined by Red Admirals, Peacocks and Small Tortoiseshells. These can be encouraged to our gardens by growing the right type of plants; buddlejas, of course, are a favourite, as are Sedum spectabile (not S. 'Autumn Joy7), asters, and several others I have noted, such as Eupatorium, Phuopsis, Nepeta, Verbena bonariense, and Liatris spicata. Several cruciferous plants such as sweet rocket, honesty and ladies smock encourage the lovely Orange Tip; the Wall, Hedge, and Meadow Browns prefer simple, tiny flowers as found on herbs such as mint, marjoram, Melissa, Nepeta, hyssop and thyme etc., which are also favoured by the pretty little Small Copper, and Holly Blue. But probably the best plants for attracting not only the butterflies, but most other insects are the umbellifers; their pollen-loaded tiny flowers, conveniently arranged in large flat heads are perfect for landing on.
Last but by no means least, I must mention moths. Two years ago we started trapping moths for study and recording. We installed a mercuryvapour lamp over a dustbin filled with egg-cartons, switched on and waited. The results were astonishing; we recorded from May to October 250 species in our garden, including a rare migrant (two in the last ten years), and one never recorded in Lincolnshire before. Unless one uses this form of catching moths it is impossible to examine them carefully, without harming them. After they have been recorded, while resting in the cartons, they are then placed into a box and taken to another part of the garden, where as soon as it is dusk, they will fly off again. There are many attractive moths that usually go unnoticed during the day, owing to their ability to camouflage themselves against their chosen resting place. Hawk-moths are some of the most impressive, if only for their size; we recorded six of these, the Elephant, Lime, Poplar, Eyed, and Convolvulus, which is a migrant. Night-scented plants will attract them into the garden, in particular, honeysuckle, and the tobacco plant. The Convolvulus and Privet Hawks are quite spectacular with a wingspan of up to 12Qmm. (almost 5 inches). Perhaps the most attractive are the Eyed Hawks which, when disturbed, will reveal hind-wings of and commonest with us is the Elephant Hawk, which is pink and ochre or olive-green. This year we noticed lots of its huge larvae on the bogbean in our pond; they are large, fat caterpillars of green or brown with 'eyes', which they expand by drawing in their head, thus looking frightening to their predators. Their natural food-plant is rose-bay willow herb, though I think they are also partial to a munch or two of Fuchsia; but who would deny this wonderful creature a feed, if only to see it visiting our gardens as a beautiful adult moth. So next time you stamp on that beetle or spray those aphids, think twice, they may have their uses after all.
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LATHRAEA clandestina
by Aileen Stocks 2001
I was inspired to investigate this group of plants when, during the talk (at the April meeting) by Alison Davies, we were shown a slide of Lathraea clandestina This appeared to be a sheet of mauve flowers blooming in early spring on bare ground. I would suspect that many in the audience had never seen these before, myself included. A little detective work revealed an interesting group of plants parasitic on tree roots.
L. clandestina (also known as Purple Toothwort) derives its generic name from an ancient Greek word meaning secret, hidden, covert and the specific name reiterates this descriptive feature of a parasitic plant whose life-cycle is spent deep underground. It is not native to the British Isles but has been present here for a long time and although not common is now widespread throughout, chiefly among the roots of willow, hazel and poplar. Obviously it grows well in the Cambridge Botanic Garden as the slide showed and according to Richard Mabey's Flora Britannica, can be found in Berkshire growing above the ground in a crook of a riverside willow.
There is a native relation – L squamria (Toothwort), but this has a pallid, insipid flower compared with L. clandestina. Again, it is found throughout Great Britain on similar host trees, like hazel and elm, but is not common. It is a native to Lincolnshire. Both of these plants belong to the family Orobanchaceae and are related to the Broomrapes.* There are about 10 different members of this family native to the British Isles. Many are difficult to identify easily and usually have a very specific host plant. In Lincolnshire five have been recorded, namely O. purpurea, O. rapwngenistae, O. alba, O. etatior and O. minor.
I have tried to grow O. hederae (Ivy Broomrape) in the past but without success.
*Rape comes from the Latin rapus meaning turnip, possible refers to the 'root' shape
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WHY NOT ENJOY THE CELANDINE?
Ruth Ward puts 1994
Recently I was in a gathering of gardeners (now there is an object for competition: what collective noun would be suitable for gardeners?), when the conversation turned to what one should do about celandine. I really feel the best would be to sit back and enjoy nature's bounty. What a glorious plant it is, with all the qualities we look for: such generous leaves, positively gleaming with health, such glowing golden stars welcoming every ray of early spring sunshine, and reminding us of summer's warmth and colour. It clothes any bare patch long before other foliage has made an appearance, and by midsummer has gone again, leaving space for the less efficient plants we cherish so much more kindly. What a range of conditions it will tolerate, too. When I had a tiny, over-shaded, ill-drained, suburban plot of heavy clay in a continental climate with heavy rainfall, there was the celandine, cheering me and driving me mad. Now I have an open, well-drained, sandy soil and a low rainfall – and masses of celandine, which flower even more generously.
In my experience, there is just one time when celandine can be effectively weeded, and that is when the weeds are well up but the flowers not yet open. At this point the roots hold firm and do not shed all the individual tubers; there are no seeds, and the little bulbils in the leaf axils have not yet developed. I have in fact, never observed these bulbils in Lincolnshire, but in our Swiss garden the the main means of propagation. Then, of course, the whole lot must be burnt – not one scrap on the compost heap. Putting them in the dry ditch just outside the garden hedge seems very effective, too. They would look very pretty there, and every year we try this, but so far none have taken hold. Naturally – or unnaturally – there are probably effective weed-killers, though I have never been that desperate. But, so long as they are not ruining a cherished planting scheme, why not just relax and enjoy the celandine's bonus display?
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THE YELLOW PERIL
by Cliff Curtis
Ranunculus ficaria, our common celandine, is a plant of our hedgerows, ditches, old gardens and churchyards, which carpets the ground in spring with golden flowers. To many gardeners the celandine is a pestilential weed, with its root system made up of tubers which break up when each piece in turn produces another plant. A common British name is Pilewort because it is said that the tubers look like haemorrhoids!
Celandines are a widely distributed native plant and are found across a wide area of Europe, and surprisingly, in Canada and the United States.
They are easy plants to grow, love growing between shrubs. Damp winters and dry summers seem not to affect growth; neutral soil conditions are preferred. In mild winters flowers appear as early as December and continue into April. Plenty of seed is produced and germinates freely but should perhaps be removed to keep colonies in check. Usually the leaves disappear by the end of May.
The National Collection holder John Carter from 'Rowden Gardens', Brentor, Devon has in excess of 100 varieties. Recommended by him are: 'Tortoiseshell' – has bold and large foliage, mottled with shades of green and red on a bronze background. 'Brambling' – leaves are dull bronze overlaid with filigree of lichen green. 'Brazen Hussy' – a form with dark, shiny, chocolate leaves. 'Collarette' – a double yellow with a central boss. 'Coppernob' – a wonderful plant with the foliage of 'Brazen Hussy' but glowing, dark orange flowers.
The last named being the first attempt at hybridisation by Mrs. Perry of Bosvigo, near Truro. 'Brazen Hussy' crossed with R. aurantiacus. I appear to be one of the local enthusiasts of this little plant in its many forms. I have to say that I grow many forms in pots, which restrains them a little, in the garden some as you may guess really go mad and require careful thought as to where to set them.