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Salix viminalis L., Osier

Account Summary

Introduction, archaeophyte, deliberately planted, common.

Eurasian temperate, also widely naturalised.

1900; Praeger, R.Ll.; Co Fermanagh.

April to December.

Growth form, status and preferred habitats

The long, narrow, untoothed leaves, with their narrowly inrolled margins, covered underneath with adpressed, silky, silver hairs, make this a very distinctive tall shrub. S. viminalis is one of the most common willow species of damp ground throughout lowland B & I.

Variation within the species is not great, but hybrids are freely formed with numerous other sallows and osiers and several of these crosses have been rarely recorded in Fermanagh. Fortunately the species is easily distinguished from the hybrids by its long leaf with straight, silky hairs on the under-surface.

In Ireland, Osier, or Common Osier, has long been regarded as a much-planted introduction for basket canes, eg Mackay (1836) and Cybele Hibernica 1866 (p. 269), the latter commenting, "scarcely wild". This has probably also been the supposition in Scotland (New Flora of the BI). Very recently, S. viminalis has also been recognised as a naturalised ancient introduction (ie an archaeophyte), throughout the whole of these islands (New Atlas; Preston et al. 2004).

S. viminalis is a common and widespread relict of cultivation and a naturalised escape throughout Ireland, found in a wide range of wet to damp ground situations usually near water. In our damp Atlantic climate, the species behaves as a pioneer colonist, self-seeding, naturalising and increasing vegetatively once it becomes established in well-lit spots in hedgerows, along roadsides, in ditches and on any damp waste ground, eg in disused quarries and gravel pits.

Fermanagh occurrence

In Fermanagh, S. viminalis has been recorded in 228 tetrads (43.2%), making it the fourth most common and widespread willow in the VC. It is tolerant of a wide range of moderately acidic to neutral, calcareous soils of variable nutrient status, but it prefers moderately fertile, sunny, sheltered sites. While it is frequently found on the somewhat higher ground of the Western Plateau, like other willows it does not venture into shade anywhere, nor on to exposed high ground or very acidic, ombrogenous peatland. Full light is critical for sustained growth of any kind of willow, tree or shrub, species or hybrid, and any shaded part of a plant soon dies away (White 1992).

Fermanagh never seems to have had the large-scale, well-developed cane willow industry one might expect in a county geographically so well suited to it. The main area of intensive willow cane and commercial basket production in NI of the 19th and early 20th centuries was in the SE corner of Lough Neagh near Lurgan. The other major Irish willow plantations were along the River Shannon in Co Limerick and in the fertile river basins of the Suir, the Blackwater and their tributaries in E Munster (Hogan 2001). An ample water supply is essential for successful seedling development of willows, but established mature plants are much less demanding in this respect, although wet ground also facilitates or enables vegetative reproduction, involving layering, suckering and rooting of detached twigs.

European origin and modern uses

S. viminalis is probably of Russian or N Eurasian origin and Meikle (1984) suggests it may have spread westwards with early man, since its long, straight, strong and very flexible young shoots are, or rather, were, very widely planted and harvested, chiefly for basket-making. Often Osier stools did not yield ideal basket canes however, since the very rapid growth rate tended to make them too brittle. Nowadays, named clonal forms and hybrid S. viminalis varieties are widely planted along roadsides and around buildings for amenity landscape or screening purposes. The material used by landscape contractors is invariably imported from European horticultural sources and inevitably this will introduce additional alien genetic variation, some of which might prove invasive or introduce associated pests or diseases (White 1992). Cultivars of S. viminalis are also being used for experimental short-rotation biomass projects in research areas including alternative energy sources, or processed as cattle fodder.

Threats

None.