Lobelia urens (Heath Lobelia)
A rhizomatous perennial herb of rough pastures and grassy heaths. It is confined to infertile acidic soils that are often seasonally waterlogged. Reproduction is by seed, which may be long-lived, and germination seems to be stimulated by disturbance. Most populations fluctuate erratically in size. Lowland.
L. urens has decreased gradually and it is now known from only six localities. Populations have been lost to afforestation and agricultural improvement, with continued threats from lack of appropriate habitat management, especially coppicing.
Oceanic Southern-temperate element.
Count of 10km squares in Great Britain: 12
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -0.19
RDB Species Accounts
Lobelia urens L. (Campanulaceae)
Heath lobelia, Bodoglys Chwerw
Status in Britain: VULNERABLE.
Status in Europe: Not threatened.
L. urens grows in open communities of rough pastures and grassy heaths, often on the margin of woodland on infertile acid soils. Extant populations are in low-lying terrain, often valley bottoms. The soils of such areas are often seasonally waterlogged and, although the surface horizons at some sites are predominantly freely draining sandy loams, they overlie more clayey horizons (Findlay, et al. 1984). Associated species include Juncus articulatus, J. conglomeratus, Lotus pedunculatus, Mentha aquatica, Molinia caerulea, Potentilla erecta, Pulicaria dysenterica and Salix cinerea.
This species is a rhizomatous perennial herb. Overwintering rosettes of lanceolate, slightly serrate leaves each produce a single flowering spike 10-100 cm high the following spring. The spike typically has 40-80 purple flowers between June and October. The flowers are entomophilous but can self-pollinate, and seed is copiously produced. After seed ripening the flowering spikes die back and new rosettes emerge from the rhizome. In damp weather dehiscence and dispersal may be delayed.
L. urens is confined to southern coastal counties of England - Cornwall, Devon, Dorset, Hampshire, Sussex and Kent, with a single record from Herefordshire. The number of localities has declined steadily from nineteen to six. Andrew's Wood, Devon, has historically held the largest population of L. urens in Britain, and currently supports about 3,500 plants. Hurst Heath, Dorset, has sustained a similar number over the last twenty years through active management of the habitat, including rotavating. The population at Flimwell, Sussex, increased dramatically from fewer than 200 to over 2,000 plants following woodland clearance in 1990 for a bird park. The remaining three extant populations in Hampshire, East Devon and Cornwall are small, each with fewer than 100 plants. Populations are monitored at most sites. Erratic fluctuations in the size of colonies increase their vulnerability.
Five colonies in southern England have been lost this century through afforestation and cultivation. The main threat to today's extant populations is lack of appropriate management. L. urens requires open ground for its establishment from seed. Ideally this would be achieved by disturbance either using horses and cattle (many sites were originally used as rough grazings) or by coppice rotation. However, adult plants are very susceptible to such disturbance and therefore a balance between recruitment and maintaining established plants must be reached. Adults are shade tolerant and have a life span of more than six years. The seeds of L. urens are small and compact and are thus likely to be persistent in the soil (Thompson, et al. 1993). Hence occasional disturbance would allow the establishment of recruits from the seed-bank and a subsequent enhancement of the population.
L. urens has a Lusitanian distribution, extending from Morocco, Madeira and the Azores along the Atlantic coast through Portugal, Spain and France to Belgium (Brightmore 1968; Daniels 1990; Tutin 1976). It reaches its northern limit in Britain.
Genetic aspects are discussed in Daniels, et al. (1996).
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.
Atlas text references
Biological Flora of the British Isles. No. 112. Lobelia urens L,
, Journal of Ecology, Volume 56, p.613-620, (1968)
Vergleichende Chorologie der zentraleuropäischen Flora. Volume 3. 2 vols,
, Jena, (1992)
British Red Data Books. 1. Vascular plants, edn 3,
, Peterborough, (1999)