Monday, 23 May 2011

A bed with a sting

Most of us have a natural aversion to stinging nettles. We steer clear of them because of a childhood encounter and the resulting burning sensation of the nettle’s sting. This sting is part of the plant’s defences, an attempt to deter the attentions of grazing herbivores that might otherwise tuck into the nettle’s succulent leaves. The gardener’s tolerance is equally low, viewing these vigorous, long-lived plants as unwanted and troublesome invaders of newly disturbed ground (like flowerbeds). They do particularly well on fertile soils of the type found around human habitation. You have to admire them though, both for their almost universal adaptability and for their resilience.

There are two species of stinging nettle in the county: the familiar Stinging Nettle Urtica dioica (which is a perennial) and the more local Small Nettle Urtica urens (which is an annual). A third species, the Roman Nettle Urtica pilulifera, once occurred around King’s Lynn and Yarmouth but is now considered extinct in Britain. It was last recorded in the county around 1900.

The dioica part of the Stinging Nettle’s scientific name is derived from the Greek (­di-oikos), which means ‘two houses’. This refers to the fact that the nettle has separate male and female plants; male plants have flowers that are dusted bright yellow by the pollen on the anthers, while female plants have flowers which show a silvery, almost furry, appearance. Very occasionally a nettle plant may be found which has both male and female flowers, with part of the inflorescence having male flowers and part female. Other variation is associated with the sting, in that there are forms of the plant that lack the sting altogether. These tend to have rather long and narrow leaves and are most often found in wet situations like fens and marshes. This form of the plant, known by some as the variety subinermis and by others as Urtica galeopsifolia, is fairly common at Wicken Fen.

As someone who spends a lot of time in and around nettle beds I know that nettle clumps support a diverse community of invertebrate life, from bright green weevils, through the caterpillars of various moths to various bugs and beetles. They also provide nesting cover for some of our warblers, particularly where the nettles rise up through thicker material like bramble or the dead stems of last year’s growth. Whitethroats and Garden Warblers seem particularly fond of them. Nettles are an important habitat and it is a shame that we view them with such distaste. One feels that if it wasn’t for the sting we might be more tolerant, and perhaps admiring, of them. Of course, they would probably then be ravaged by grazing herbivores and far less impressive.

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