Family: Caesalpiniaceae
Common Name: Senna, Cassia

This genus is found in tropical and temperate regions throughout the world. The evergreen or deciduous shrubs and trees have pinnate leaves, showy, mostly yellow flowers, and flattened or cylindrical, sometimes winged, pods. Dried pulp from some species' pods yields the medicinal drug, senna. Many species now in this genus were formerly classified as Cassia.

Species

S. artemisioides, silver cassia, an Australian native, to 1.5 m (5 ft), is low-branching, with silvery gray leaves, pale yellow flowers and flattened pods.

S. candolleana (Synonym: S. bicapsularis), a shrub to 3 m (10 ft), has thickish leaves comprising three to five pairs of leaflets and bright yellow flowers in late summer and autumn. The slender pods are bean-shaped.

S. didymobotrya is a shrub growing to 3 m (10 ft) high. The flower spikes, to 30 cm (12 in) long, are held on the stern tips. Yellow blooms appear intermittently, but the main flowering period is autumn and winter.

S. multijuga is a decorative small tree, growing 6-8 m (20-26 ft) high. Its very long leaves contain between 18 and 40 leaflets and the large, yellow flowers are followed by flattened pods.

Cultivation

In areas prone to frost, grow in an intermediate to warm conservatory or green-house, in pots of soil-based potting compost. Ensure maximum light and a moderately humid atmosphere. Never overwater plants and in winter be even more sparing. Pruning may be needed to restrict size, but only lightly prune S. artemisioides as it dislikes pruning, and never cut into the old wood of this species. Prune after flowering. Propagate in spring from seed germinated at 21°C (70°F), or from semi-ripe cuttings in summer, with basal warmth.

Climate

Zone 10 or tropical.