This is one genus (the other two being genista and spartium) of the trio collectively known as brooms. Nearly all species of cytisus have the small pea-typetypical of the family, but in other respects they differ widely. There are prostrate kinds with creeping underground such as pale purple Cytisus purpureus; low, widespreading kinds such as cream-coloured C. kewensis; 12 to 18-in, small bushes such as bright yellow C. beanii; medium-sized bushes such as 3-ft. Sulphur-yellow C. praecox, and tall bushes such as 6 to 8-ft. C. multiflorus, better known as the white Spanish broom. All these are April or May flowering as are the numerous varieties and hybrids of the common broom, C. scoparius, available in yellow, yellow and crimson, cream, pink, cerise and crimson varieties and all making bushes 5 to 6 ft. high. By contrast C. battandieri, 6 ft. or more, does not commence to produce its erect spikes of yellow, pineapple-scented flowers until June and its silky grey are quite large. All the foregoing are deciduous.
C. monspessulanus and C. Porlock are evergreen, 6 to 8 ft. high, with yellow flowers in spring and early summer, sweet scented in Porlock. Unfortunately they are less hardy and therefore most suitable for southern, western and maritime gardens.
All brooms succeed best in sunny places and well-drained, moderately acid or neutral soils. Most can be pruned moderately immediately after flowering and C. battandieri can have old stems cut back to young side growth in spring.