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Saturday, November 27, 2010

Tibouchina urvilleana

Our garden is currently hidden under several inches of snow but the Tibouchina urvilleana plants in our small conservatory, which would be more at home in tropical Brazil than in freezing north-east England, are in full flower. Each bloom only lasts for a couple of days but they are produced in a long succession through the darkest months of winter. These plants have very unusual flowers, with two types of stamens. The lower, claw-shaped ones are the genuine article, producing pollen that is squeezed out of a pore in their tip when they are pushed downwards, but the upper ones with pale tips are sterile 'food' stamens that attract bees. They use the pollen- bearing stamens as a landing pad and unwittingly transport the pollen.

Tibouchina urvilleana grows into a greenhouse shrub but old, woody plants soon become shapeless and their brittle stems easily snap. I've found that the best way to grow them is to take semi-ripe cuttings in summer, when they root very easily, producing compact plants with plenty of 3 inch diameter flowers from November onwards.

Tuesday, November 23, 2010

Stinking iris,Iris foetidissima

Stinking iris Iris foetidissima has two memorable features. The first is the vibrant orange seeds that are revealed when the seed pod bursts open. These make excellent decorations and I have a vase of them on my desk as I write.
Each seed is surrounded by a soft orange aril, which slowly dries and wrinkles once it's exposed to air.
The other memorable feature isn't the flower, which is unspectacular by the standards of many irises, but the smell. If you crush the foliage between finger and thumb you release an aroma that's reminiscent of roast beef or, perhaps more accurately, the exaggerated beefy smell of a packet of roast beef-flavoured crisps. The species is sometimes known as roast beef plant.

Iris foetidissima is easy to grow from seed and thrives on a dry, sunny bank in my garden, producing seed pods for winter decoration every year.

Wednesday, November 10, 2010

Barley, Hordeum vulgare

Gardening with grasses has become popular in recent years and garden centres are full of examples - many of which, I have to say, look pretty unexciting to me. So I've always been surprised that gardeners don't cultivate some of our cereals, like wheat, rye, oats and the barley Hordeum vulgare pictured above for their decorative properties. Maybe it's just that they are such familiar plants in the landscape, but for sheer architectural beauty they really are very attractive - and the barley variety that I recently found preserved on an old herbarium sheet in Durham University School of Biological and Biomedical Sciences must have been especially so when it was alive and growing.

This particular plant has purple grains. Let me begin by quoting the attached label, that outlines its provenance.

Huskless Barley from Thibet (sic)
This ear of barley was grown at Burton-on-Trent by me in 1890 from seed given by the late Horace T.Brown,F.R.S. He got it from the late Thistleton Dyer, Director of Kew Gardens, who got it from Mr. Duthie of Sharanpur Botanical Gardens. He says the seed came from Poo in Thibet about the year 1881 when it was introduced into the Punjab, with other varieties. Dr. H.T.Brown says in some notes on this barley (Transactions of the Burton Natural History Society), “The colour is not diffused through the paleae, as in black Abyssinian or Scotch barley, but is confined to the integuments of the caryopsis. When microscopically examined, the inner protions of the pericarp immediately adjacent to the testa are seen to be charged with a very dark purple pigment, appearing in mass almost black. This pigment is fairly soluble in water, and probably consists of modified chlorophyll”.......“ The peculiar colour is not confined to the grain only, but occurs also in the nodes of the straw, which even at an early period of growth are very dark purple.” The colour appears to have faded somewhat during all the years that the specimen has been kept. I have tried two or three corns recently but failed to get any sign of germination. John E. Nowers. Jany 9 1928.

Huskless barleys like this, with grains that outgrow the papery glumes that normally enclose them tightly, have been cultivated for at least 8000 years and would have been prized by early farmers because their grains are easily separated from the papery chaff. The great 13th. century traveller Marco Polo, visiting the province of Badashan in what is now part of Afgahistan, mentions the crop:
"The mountains of this country also supply Saker falcons of excellent flight, and plenty of Lanners likewise. Beasts and birds for the chase there are in great abundance. Good wheat is grown, and also barley without husk."

When samples were brought to Britain in 1884 by the Mr. Duthie mentioned in the herbarium specimen label above, some were give to John McDougall, the flour miller, for evaluation as a malting grain. He noted that it sprouted well "but the colour comes off and so will not do for pale ales, but it would do well for stout. For feeding purposes it would be useful, although it would take time to remove prejudice for its colour"....

Regretfully Mr. Duthie conceded "The objection as to colour,alluded to in the report, is fatal to its value and will prevent it every being grown, except as a curiosity...."

There was, however, considerable interest in a white-grained variety of the huskless barley, which continues to this day in the malting industry, as evidenced by this research paper published in 2009 entitled 'Potential of Hull-less Barley Malt for use in Malt and Grain Whisky Production'. Huskless barley has come a long way in the last 8000 years.

Meanwhile, I'd love to get my hands on some viable seed of the purple-grained variety, to grow for its decorative properties in my garden.... as a curiosity, as Mr. Duthie suggested back in 1888.

The source of some of the above information is the Bulletin of Miscellaneous Information (Royal Gardens, Kew) No.23, 1888,pp. 271-273, which also contains more detailed information on Dr. Brown's anatomical studies on the grain.

Sunday, November 7, 2010

Lunaria annua, Honesty

Lunaria annua, commonly known as honesty or money plant, is an example of a species that's more attractive dead than alive. After the flattened fruits, known botanically as siliculas, have shed their seeds the central translucent septum of the silicula remains attached to the plant well into winter and looks especially striking when back-lit by low winter sunlight. The silvery appearance of the discs, resembling coins, accounts for the common names.

After pollination the ovary of honesty develops into a flattened disc-shaped silicula and when it's brightly lit by sunlight you can see the six kidney-shaped seeds developing inside. When it ripens the two outer walls separate from the central septum, the seeds blow away...........

 and only the papery central septum remains attached to the plant.

Honesty is a member of the cabbage family, Brassicaciae, whose members typically have four petals arranged in a  cross (explaining for the old name of the family, Cruciferae). The purple flowers of honesty aren't especially attractive, unless you happen to be an orange tip butterfly like this one, visiting to collect nectar.

Tuesday, November 2, 2010

Malus x zumi var. calocarpa 'Golden Hornet'

When you only have a small garden plants that perform more than once in a year are particularly valuable and there can't be many that put on a better display than Malus 'Golden Hornet'. In spring the branches almost disappeared under a dense covering of blossom that hummed with bees for about ten days ........

.... and this is the result of their work - a crop of crab apples that's so heavy that it threatens to break the more slender branches. Birds seem to leave these yellow fruits alone until the harder months of winter, when the apples have been softened by frost - and then the blackbirds move in. For most of the last decade the bark of my tree has been disfigured by an infestation of wooly aphids but it seems that last winter's prolonged frost and snow killed them. There's a lot to be said for the occasional really hard winter; this year the tree was pest-free