Ulex europaeus (gorse): 2.5m, good on poor soil
Ulex gallii (western gorse): 2m, thrives in sandy, acid soil.
Ulex minor (dwarf furze) 30 centimetres (12 in) sandy lowland.
Ulex (gorse, furze or whin) are a species of evergreen flowering plant in the family Fabaceae, native to Britain and many parts of Europe. Common on open moorland. The genus Ulex comprises about 20 species of thorny evergreen shrubs.
The most widely familiar species is common gorse (Ulex europaeus), the only species native to much of western Europe, where it grows in sunny sites, usually on dry, sandy soils. It is also the largest species, reaching 2–3 metres (7–10 ft) in height; this compares with typically 20–40 centimetres (7.9–15.7 in) for western gorse (Ulex gallii).
(Ulex gallii) This latter species is characteristic of highly exposed Atlantic coastal heathland and is widespread on Dartmoor in Devon. Dartmoor is the largest and highest upland in southern Britain, exposed to strong winds and high rainfall. The soils are acidic and the area has been relatively undisturbed by intensive agriculture. This upland heathland supports much wildlife including meadow pipits, stonechats, and skylarks as well as adders, lizards and the distinctive emperor moth caterpillar. Also supports red grouse and ring ouzel.
In the eastern part of Great Britain, dwarf furze (Ulex minor) replaces western gorse. Ulex minor grows only about 30 centimetres (12 in) tall, a habit characteristic of sandy lowland heathland.
Common gorse flowers a little in late autumn and through the winter, coming into flower most strongly in spring. Western gorse and dwarf furze flower in late summer (August–September in Ireland and Great Britain). Between the different species, some gorse is almost always in flower, hence the old country phrase: “When gorse is out of blossom, kissing’s out of fashion”. Gorse flowers have a distinctive coconut scent, experienced very strongly by some individuals, but weakly by others
Gorse may grow as a fire-climax plant, well adapted to encourage and withstand fires, being highly flammable, and having seed pods that are to a large extent opened by fire, thus allowing rapid regeneration after fire. The burnt stumps also readily sprout new growth from the roots. Where fire is excluded, gorse soon tends to be shaded out by taller-growing trees, unless other factors like exposure also apply. Typical fire recurrence periods in gorse stands are 5–20 years.
Gorse thrives in poor growing areas and conditions including drought; it is sometimes found on very rocky soils, where many species cannot thrive. Moreover, it is widely used for land reclamation (e.g., mine tailings), where its nitrogen-fixing capacity helps other plants establish better.
Gorse is a valuable plant for wildlife, providing dense thorny cover ideal for protecting bird nests. In Britain, France and Ireland, it is particularly noted for supporting Dartford warblers (Sylvia undata) and European stonechats (Saxicola rubicola); the common name of the whinchat (Saxicola rubetra) attests to its close association with gorse. The flowers are sometimes eaten by the caterpillars of the double-striped pug moth (Gymnoscelis rufifasciata), while those of the case-bearer moth Coleophora albicosta feed exclusively on gorse. The dry wood of dead gorse stems provides food for the caterpillars of the concealer moth Batia lambdella. (Wikipedia)
Webster lists the following species in his Flowering Trees & Shrubs
ULEX EUROPAEUS.—Furze, Gorse, or Whin. This pretty native shrub needs no description, suffice it to say that it is one of the handsomest-flowering shrubs in cultivation. U. europaeus flore-pleno (Double-flowered Gorse) is even more beautiful than the species, the wealth of golden flowers almost hiding the plant from view. U. europaeus strictus (Irish Furze) is of more erect and slender growth, and less rigid than the common species.
U. NANUS.—-Dwarf Gorse, Cat Whin, and Tam Furze. This differs considerably from the common plant, not only in stature, but in the time of flowering. In this species the bracts at the calyx base are small compared with those of U. europaeus, while the smaller flowers are produced during summer, and when not a bloom is to be found on its supposed parent. It is of dense growth, the tallest stems rarely rising from the ground to a greater height than about 15 inches.
All the Furze family succeed admirably in the poorest of soil; indeed, a dry gravelly bank would seem to be their favourite haunt.