Parasitic mistletoe plant alien to native flora

Another Life Michael Viney The brilliant flare of rowans along the mountain roads in August announced a spectacular autumn crop…

Another Life Michael VineyThe brilliant flare of rowans along the mountain roads in August announced a spectacular autumn crop of berries of all kinds. Only those with a dogged faith in tradition will want to predict a hard winter (nature doesn't do proactive, even during climate change), but there's no doubt that the whole thrush family, in particular, will appreciate the bounty of trees and hedgerows in months to come.

Our own hawthorn hedges have lost most of their berries while my back was turned and inside the acre the early-morning blackbirds have begun to strip the brightest bush for miles: a wall-grown firethorn (pyracantha), its branches crusted with vermilion fruit right up to the slates. Of all the thrush family, the blackbird turns to berries most ardently in autumn, when almost two-thirds of its food is vegetable. Blackcurrants, elderberries, blackberries, rosehips have all been plucked in their turn, and only a net across the open door of the polytunnel kept the birds from eviscerating the last ripe tomatoes.

A more candid militancy is that of pairs of mistle thrushes which, finding a heavily berried holly tree in their territory, guard it for weeks as their exclusive food supply. This also applies to the clumps of white berries that gave the birds their name, but the thousands of mistle thrushes that flock into Ulster and Leinster from northern Britain in winter are moving between countrysides where mistletoe is scarce indeed.

The actual occurrence in Ireland of this parasitic plant, quite alien to the native flora, has intrigued botanists for decades. Records accumulating in recent years have encouraged Dr Charles Nelson (now domiciled in Britain, but still one of Ireland's keenest plant historians) to attempt as complete a survey as possible of past and present locations*.

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So far, the map of living mistletoe shows about a dozen locations, five in the North and most of the rest in the south-east and Dublin.

Viscum album (meaning "white and sticky"), one of some 1,300 mistletoe species worldwide, thrives as a native in France, where roadside poplars - mistletoe's frequent choice after cultivated apple trees - can be strung with dozens of bushes like the verdant hanging baskets of Tidy Towns, and the cider-apple orchards of Normandy and Brittany supply mistletoe to the Irish Christmas market. In Britain, the plant is amply and mysteriously concentrated in the south and west midlands, mostly in gardens and old orchards, but also on parkland lime trees and churchyard hawthorn hedges. A public survey organised in the 1990s received some 12,000 winter sightings.

Mistletoe undoubtedly reached Ireland originally with imported apple trees, but it has also been cultivated here and there for some two centuries. In nature, mistletoe is spread by birds which, eating the berries, either wipe their bills on a branch or eject seeds in a dropping in record time (even, in some Australian birds, helpfully wiping their bottoms along the bark). Cultivation runs a similarly high risk of failure as seeds come unstuck, dry up or are eaten before they can germinate and penetrate their nutrient supply of their hosts. The most promising procedure, using 20 or so fresh seeds in February (not the withered remnants from an office party) can be found at www.mistletoe.org.uk, an encyclopedic website on the plant.

Cultivation began in the National Botanic Gardens at Glasnevin in 1804 or even earlier (it was founded in 1795).

By the 1870s there were at least a couple dozen branches of mistletoe growing on six different kinds of tree but it took until the 1980s for any real expansion. This included an old Bramley apple tree in a neglected neighbouring garden, making Glasnevin the biggest known colony of mistletoe in Ireland.

Orchards in Waterford, Wexford, Carlow and Limerick have produced some flourishing locations, but Dr Nelson is surprised to find no specific records from the apple-tree counties of Kilkenny and Armagh. He is also puzzled that, while folk remedies involving mistletoe have been retrieved from Cavan and Meath (for soothing the nerves) and Limerick and Cork (for relieving epilepsy), the actual presence of the plant has been scanty or unknown.

The druidical significance of mistletoe, found across most of Europe, probably had origins in the plant's life-affirming crown of greenery at the peak of bare branches in mid-winter, and the semen-like promise of the juice around its seeds (are you sure you want that kiss?).

Today, mistletoe is a serious contender in research into traditional plant medicines. Just as yew has produced taxol, mistletoe's impact on human cells and the immune system may find a role in cancer relief to extend its present wide use in the alternative remedies of continental Europe.

* Location reports should be e-mailed to Dr Charles Nelson's at tippitiwitchet@zetnet.co.uk or sent by post to Tippitiwitchet Cottage, Hall Road, Outwell, Wisbech, Cambridgeshire, PE14 8PE, UK