Most of the species of Erica are small shrubs from 20โ150 cm (8โ59 in) high, though some are taller; the tallest are E. arborea (tree heath) and E. scoparia (besom heath), both of which can reach up to 7 m (23 ft) tall. All are evergreen, with minute, needle-like leaves 2โ15 millimetres (0.079โ0.591 in) long. Flowers are sometimes axillary, and sometimes borne in terminal umbels or spikes, and are usually outward or downward facing. The seeds are very small, and in some species may survive in the soil for decades.