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Thursday, April 29, 2010

Wood Anemone, Anemone nemorosa

Yes, it is a wood anemone Anemone nemorosa, but not as we know it Jim (as Mr. Spock on StarTrek might have remarked if he'd landed on a distant planet and found this growing on an alien woodland floor). It's a mutant, where a mutation in one of the genes that controls the formation of the whorls of floral structures has converted all of the ovaries, that would eventually contain the seeds, into petal-like structures. With its seed production disabled, it can only reproduce vegetatively via its underground rhizome and since that grows very slowly this isn't a plant that's often found in garden centres. It's been growing in my garden for about a decade and has formed a patch with about 20 flowers that's only about 30cm. in diameter.
Compare the wild-type wood anemone above with the mutant below and you'll see the scale of the floral derangement. Gardeners (and I'm no exception) have always been fascinated by rare mutant forms of wild flowers that occasionally turn up - some are even described in John Gerard's Herbal of 1597, which lists, amongst others, the childling daisy.
These days geneticists deliberately produced floral mutants like this, using chemical mutagens, to identify the genes that are involved in floral development, using the little weed known as thale cress Arabidopsis thaliana, which grows conveniently quickly in the laboratory but was definitely at the back of the queue when the genes for aethetic appeal were handed out.

Saturday, April 24, 2010

Tulip tree, Liriodendron tulipifera

I should have planted a tulip tree Liriodendron tulipifera in my youth. I've hankered after one ever since I first saw a magnificent specimen in the garden of The Wakes, Gilbert White's home at Selborne in Hampshire, about 40 years ago. It's a bit late to plant one now, because they take a decade to reach flowering size..... but on the other hand there is an old gardening adage that says that you should plant as though you're going to live for ever - so maybe I will. The handsome, cup-shaped flowers are usually carried high up on the tree, so you need binoculars or  telephoto lens to admire them...
... but you can appreciate the unusual leaves from ground level. Each looks as though it has been snipped off at the tip with a pair of scissors. When they first emerge from the buds in spring they're on long stalks and the leaf is folded up the middle, lengthways, so each looks like a miniature flag - until the blade unfolds, rather like a book opening.

Liriodendron tulipifera is native to the eastern United States, where it grows to a height of 180 feet ............ not, then, a tree for a small suburban garden, but space isn't a problem when your botanic garden is digital.

Saturday, April 17, 2010

English Florists' Tulip, Tulipa sp.

English florists' tulips have been grown in England since the 17th. century, when they probably arrived here from Holland, and they have been lovingly cultivated by members of the Wakefield and North of England Tulip Society since 1836, who hold an annual show and exhibit their prize blooms in beer bottles. The flowers are notable for their elegant half-cup shape shape and, rather more remarkably, the fact that they are – strictly speaking - diseased. The vibrant colour patterns of the tepals is caused by a virus infection – tulip breaking potyvirus – that’s transmitted by aphids. Pigment production in tepal cells that are infected is drastically altered, causing the colour patterns that have acquired their own distinct nomenclature. Plain coloured, uninfected flowers are known as ‘breeders’ while bulbs that are infected are said to be ‘broken’. Flowers with pigmented tepal edges are said to be ‘feathered’, those with a strong column of colour in the centre of the tepal are ‘flamed’ and spectacular colour patterns like the one above are known as ‘bizarres’, while ‘bibloemens’ are predominantly white with delicate purple or blackish-purple markings.

The patterning produced by the virus infection is unpredictable, but once a bulb has been 'broken' and has been recognised as having a desirable colour pattern it can be propagated vegetatively from bulblets that are produced every year.

Image Source:

During the height of Tulip Mania in the 17th. century bulbs of virus-infected tulips like like this Semper Augustus changed hands for the equivalent of ten years wages for a skilled craftsman.

Friday, April 9, 2010

Scarlet Runner bean Phaseolus coccineus

Growing vegetables in the flower border has become fashionable in recent years but here's a vegetable that always been easy to appreciate for its decorative value - the runner bean. What other climber has such vivid flowers and also makes a nutritious addition to Sunday dinner? Scarlet runner bean hails from the mountainous regions of Guatamala, Mexico and Panama so it's travelled a long way on its journey to the gardens and allotments of Britain .... and changed a good deal along the way. The seeds and pods are monstrous compared with the diminutive wild versions and the pods have been bred to reduce the stringy tissue and parchment layer in the pod wall that would make wild pods shatter and release seeds as they dry out. Runner beans are usually grown as annuals (I've just sown what I hope will be an early crop) but they are perennials in the wild and if you can keep the roots frost-free through the winter they'll produce a second year's growth, albeit with inferior pod production. If you are of a curious nature and fancy some amateur plant breeding you could try crossing French beans with runner beans, by carefully removing stamens from French bean flowers with fine tweezers before they shed pollen and then pollinating the flowers with runner bean pollen a day or two later. The cross works with French beans as the female parent, but not the other way about.

Tuesday, April 6, 2010

Angel's Trumpet Brugmansia x candida

The nocturnal scent of Angel's Trumpet is remarkable, suddenly switching on at dusk and filling a conservatory with a fragrance that can be almost overpowering. I have read a story - probably apocryphal, but never mind - that in the plant's native South America mothers wheel their crying infants in prams under these plants because the fragrance is soporific and quickly pacifies them. This particular species is a sterile hybrid and can only be propagated from cuttings. I bought the original plant for £2.50 from Egglestone Hall gardens about twelve years ago and the one in the photo is a 6th. generation clonal descendant. Taking a  cutting every other year and providing a frequent high nitrogen feed produces a 2 metre-tall plant within two years that soon becomes too big for its pot and our small conservatory and must be propagated from cuttings again. Tonight the current incarnation has ten nine inch-long blooms open and the scent pervades the whole house .... it's been flowering since November and there are still plenty of buds to open. That original £2.50 was the bargain of the century.
Seen from below, the buds have this intriguing spiral twist just before they open fully.
Brugmansia, like many members of the potato family (Solanaceae) contains extremely toxic alkaloids which, in appropriate doses, have important medicinal uses .

Saturday, April 3, 2010

Saxifrage Saxifraga x poluanglica

It's a general rule-of-thumb in horticulture that if you can replicate a plant's natural habitat and climatic preferences, you have a good chance of growing it well. Recent mild winters haven't been too kind to gardeners who like to grow alpine plants but this last winter has really delivered the conditions that alpine plants have evolved to deal with........ and as a result my alpines have done better than I can ever remember. From mid-December until late February this Saxifraga x poluanglica was buried under 30cm. of snow for 4 weeks then frozen solid in its pot. The results speak for themselves...

Saxifraga literally means 'rock breaker', a reference to the way in which these plants thrive in crevices in shattered rocks, often in the poorest of soils. Their neat cushion of foliage protects the flower buds developing within and as soon as conditions allow - often just as the snow is thawing - they bloom very quickly. Unfortunately, they finish flowering all to quickly too .............