Broom (shrub)

Broom (shrub)

Brooms are a group of evergreen, semi-evergreen, and deciduous shrubs in the subfamily Faboideae of the legume family Fabaceae, mainly in the three genera Chamaecytisus, Cytisus and Genista, but also in many other small genera (see box, right). All genera in this group are from the tribe Genisteae. These genera are all closely related and share similar characteristics of dense, slender green stems and very small leaves, which are adaptations to dry growing conditions. Most of the species have yellow flowers, but a few have white, orange, red, pink or purple flowers.

Two other close relatives are Ulex (gorse) and Laburnum (laburnum), but these differ more strongly in appearance from the brooms. Some botanists include Podocytisus caramanicus in the genus Laburnum.

All the brooms and their relatives (including Laburnum and Ulex) are natives of Europe, north Africa and southwest Asia, with the greatest diversity in the Mediterranean. Many brooms (though not all) are fire-climax species, adapted to regular stand-replacing fires which kill the above-ground parts of the plants, but create conditions for regrowth from the roots and also for germination of stored seeds in the soil.