Leucojum aestivum

NOTE: The account below is for the sub-species. Closely related species and sub-species may have separate accounts listed elsewhere in the Online New Atlas

Leucojum aestivum L. ssp. aestivum (Liliaceae)

Summer snowflake, Eiriaidd

Status in Britain: LOWER RISK - Near Threatened.

Status in Europe: Not threatened.

Most populations of L. aestivum ssp. aestivum occur in Salix carr or Alnus glutinosa woodland along muddy river banks and ditches or on islets in rivers, often in areas which are flooded in winter. In most sites, associates are generally a few other spring-flowering species such as Arum maculatum and Ranunculus ficaria, with Galium aparine and Urtica dioica usually present, but at some sites it occurs in a more diverse community (FitzGerald 1990d). Other wetland associates may include Caltha palustris, Carex riparia, Filipendula ulmaria, Glechoma hederacea, Oenanthe crocata, Phalaris arundinacea, Phragmites australis, Ribes sylvestris, Rumex sanguineus and Symphytum officinale (Farrell 1979). A few populations occur in other habitats, including damp woodland rides and under hedges. 

L. aestivum ssp. aestivum is a perennial, with leaves appearing above ground in February or March. The flowering period is generally from late March into April, but it may be earlier in a mild year. The large seeds are thought to be dispersed by water.

Most of its sites are by the Thames and its tributaries, where it is found in more than 40 1 km squares in two main areas: between Reading and Windsor, and between Goring and Abingdon. A survey in the 1970s showed that over 100,000 clumps, 77% of the total British population, was contained within six sites on the Thames from Reading to Marlow, and by Loddon near Twyford. Most of its sites hold at least several hundred clumps, though a few may hold as little as a single clump (Farrell 1979). Outside its main area, native populations occur along the Stour valley in Dorset (several thousand plants), at a few sites in Wiltshire (FitzGerald 1993), at Littlehempston in Devon (more than 4,000 plants), and perhaps a site in Monmouthshire. In the past, there has been uncertainty about the status of L. aestivum in Britain, mainly because the morphological differences between the native ssp. aestivum and the introduced ssp. pulchellum were not fully understood. The latter has smaller flowers and a narrower spathe, flowers later and the edges of the scape are not denticulate. Subspecies pulchellum is widely naturalised, mainly in southern Britain, but extending northwards to East Inverness.

Many sites for ssp. aestivum are vulnerable to development, with possible threats stemming from the construction of artificial riverbanks to control erosion, the straightening of river courses and the development of marinas and boat-moorings. Trampling of river bank vegetation could pose an additional threat, and the digging up of bulbs would be particularly damaging to the smaller colonies.

L. aestivum is widely distributed in marshes and wet meadows in Europe, from Ireland eastwards to the Netherlands and the Czech Republic, and southwards to Sardinia, Greece and the Crimea. It is legally protected in Austria, Belgium, France, Germany, Netherlands and Switzerland. A decline is reported in Russia and eastern Europe, mainly because of drainage and river engineering.

L. Farrell and M. J. Wigginton