Senna alata
Common Name: emperor's candlesticks
Type: Broadleaf evergreen
Family: Fabaceae
Native Range: Tropical Americas, Africa, Australia, southeastern Asia
Zone: 9 to 11
Height: 5.00 to 8.00 feet
Spread: 3.00 to 4.00 feet
Bloom Time: Seasonal bloomer
Bloom Description: Yellow
Sun: Full sun
Water: Medium
Maintenance: Low
Suggested Use: Annual
Flower: Showy
Leaf: Evergreen
Fruit: Showy
Tolerate: Drought

Culture

Winter hardy to USDA Zones 9-11 where it is grown in average, medium moisture, well-drained soils in full sun. Drought tolerant once established. In the St. Louis area, these plants are perhaps best grown as annuals. Start seed indoors in February-March and plant outside after last frost date. Seed can be collected from plants in fall and used for starting new plants indoors the following late winter. Container plants can be grown on patios in summer and overwintered in a greenhouse or sun room, but can be otherwise somewhat difficult to overwinter in a home. Overwintered plants should be watered very lightly in winter and then cut back in early spring to control size and shape.

Noteworthy Characteristics

Senna alata, commonly called empress candle plant or candle bush, is so named because the erect flower spikes when in bud resemble yellow candles. It is also commonly called ringworm cassia because the plant leaves were once used to treat ringworm. It is an evergreen tropical shrub or tree that typically grows to 12-30’ tall in its native habitat. In St. Louis, it can grow rapidly to 6-8’ tall in a single growing season if started by seed indoors in late winter. Features pinnately compound medium to dark green leaves (to 30” long), each with 7-14 pairs of leaflets. Bright yellow 5-petaled cup-shaped flowers bloom bottom to top in erect axillary racemes in fall. Flowers give way to winged bean-like seedpods (6-8” long) which also add ornamental interest. Cassia alata and Senna alata are synonymous.

Specific epithet means winged for the seedpods.

Problems

No serious insect or disease problems. Watch for leaf miners. Aphids and whiteflies may visit indoor plants.

Garden Uses

In the tropics, it is grown as an ornamental flowering shrub or small tree. In St. Louis, grow from seed and group or mass as an annual for its excellent foliage, architectural height and fall flowers. May also be grown in patio containers or tubs.