Wild asparagus  (Asparagus prostratus)

Classified as Vulnerable in Great Britain (2).

This plant is our native asparagus species (3) and is endemic to Western Europe (1). Recent evidence indicates that wild asparagus is a separate species to garden asparagus (Asparagus officinalis spp. officinalis) and not a subspecies (Asparagus officinalis ssp. prostratus) as previously thought (1). The stems grow prostrately (4) and have needle-like leaves, which reach 16 (exceptionally 24) mm long. The flowers are small and green (5), and produce bright red berries (2).

Once recorded from 34 sites on the coasts of southern and south-west England and Wales; it is now known from 28 sites. In England it occurs in Cornwall and in a single site in Dorset. In Wales it is known from Pembrokeshire and the Gower coast (5). It has also been recorded in Sussex and Anglesey (5). Elsewhere, the species occurs on the coasts of Spain, France, the Channel Islands, the Netherlands, Belgium, Ireland and Germany (1). It is rare and threatened in Belgium and Ireland, and may be extinct in Germany, but is locally abundant in Spain and parts of France (1).

You can view distribution information for this species at the National Biodiversity Network Gateway.

This plant mainly occurs within a few hundred metres of the sea in open, grassy vegetation, more rarely in gorse scrub (1). It occurs on sea cliffs, occasionally on sand dunes and is rarely found on shingle (1).

A long-lived perennial, the stems are produced from ‘rhizomes’ that allow the plant to slowly spread by vegetative reproduction (2). New stems are produced each year in April and May, and flower from May and June. The plants are ‘dioecious’, with male and female flowers occuring on different plants (1). Insects pollinate the flowers, and the berries, which are dispersed by birds and small mammals, begin to turn red from July to October (2).

Reported threats to this species include the trampling of cliff-top areas, soil erosion, and a widespread decline in grazing and management, leading to a decline in habitat suitability (2) resulting from the subsequent growth of grasses (6). Furthermore, a decrease in the genetic viability of some populations is likely (2). Feeding by the asparagus beetle (Crioceris asparagi) has a significant effect at some sites, and cross-pollination is an important factor in limiting fruit-set in some populations with only a few scattered plants (7).

Wild asparagus is a UK Biodiversity Action Plan priority species; the Species Action Plan includes targets to enhance the population size at all known sites, with the aims of doubling the wild population at sites with less than 10 plants (around 9 sites) by 2008 and creating an additional two populations at former sites. Surveys in 1999-2001 showed that of the 28 populations, single plants occur in 4 sites, 5 sites have fewer than 10 plants, and only three sites have more than 100 plants (5). Most of the areas where wild asparagus occurs are sites of Special Scientific Interest (SSSIs) (6). Furthermore, seeds have been collected and plants that have been raised ex-situ can be used as a source for reintroductions (2). The National Trust is the lead partner for the conservation of this species.

There may be further information about this species available via the National Biodiversity Network Gateway.

Visit the website of the National Trust:
http://www.nationaltrust.org.uk/main/

For more on this species see the UK BAP Species Action Plan available at:
http://www.ukbap.org.uk/