Previously included in Cassia and still often sold as such, these species have been reclassified as Senna—a move not accepted by all botanists. Grown for their lavish show of bright yellow, five-petaled flowers that look something like those of potentilla. Blossoms are followed by seedpods that may create litter; to reduce pod production, prune lightly after flowering. Rangy, rank growers should also be cut back periodically to encourage more compact growth. Good for screens, massing, and background plantings. Prefer well-drained soil.
Evergreen shrub, native to Australia. Grows to 3–5 ft. tall and wide, with attractive, light, airy structure. Gray leaves are divided into six to eight needle-like, 1-in.-long leaflets. Bears 3/4-in. bright yellow flowers in clusters of five to eight in winter and spring, with bloom often continuing into summer. In the desert, plants may rest in summer, then resume flowering in fall. Heavy seed production. Very drought-tolerant but looks better with moderate to regular water.
Evergreen shrub, native to Australia. Similar to S. artemisioides but with green foliage and somewhat greater cold tolerance.Senna splendida
Evergreen shrub, from Brazil. Open growth reaches 9–12 ft. tall and 6–10 ft. wide; habit varies from fairly upright to horizontal. Bright green leaves have four elliptical to oblong leaflets to 3 in. long. Loose clusters of 1/2-in. flowers appear at branch ends from autumn into winter. Heavy seed production. ‘Golden’ grows to 18 ft. tall and 15 ft. wide, with large golden-yellow blooms.
Shiny, gray-green leaves contrast nicely with golden yellow blooms on a plant that can reach...
Vine or shrub, from South Africa. If tied to a support, it can scramble 15–30 ft.; with hard pru...
From Asia Minor to central Siberia. Wiry, 12–16-in. stems rise from a clump of narrow gray-green...