Cassia fistula
 
Common Names Golden Shower Tree, Indian Laburnum, Purging Cassia, Amaltas, Ratchaphruek
 
Zones 10A–11 (outdoors); Zone 9B with protection
Cassia fistula is a spectacular deciduous tree native to the Indian subcontinent and Southeast Asia, celebrated for its cascading racemes of vivid yellow flowers. It’s the national flower of Thailand and the state flower of Kerala, India, revered for its cultural symbolism and medicinal value. In bloom, the tree becomes a golden waterfall, often leafless beneath the floral canopy.
 
Key Features
Growth Habit: Upright to spreading; open crown; fast-growing
Height: 30–40 ft. in cultivation; up to 60 ft. in optimal conditions
Trunk: Smooth gray bark; becomes rough with age; typically single-stemmed
Leaves: Pinnately compound; 6–24 in. long; 4–8 pairs of elliptic leaflets
Inflorescence: Pendulous racemes 12–24 in. long; bright yellow flowers with five equal petals; bloom late spring to early summer
Fruit: Cylindrical pods 12–24 in. long; dark brown when mature; contain multiple seeds with a pungent odor
Ecology: Attracts bees and butterflies; not a nitrogen fixer; seeds mildly toxic if ingested2
 
Growing Conditions
Light: Full sun
Watering: Moderate; drought-tolerant once established
Soil: Well-drained loam or sandy soil; neutral to slightly alkaline pH
Temperature: 50–95°F (10–35°C); tolerates brief light frost
Humidity: Adaptable; prefers subtropical to tropical conditions
Propagation: Seeds (scarify for better germination); cuttings
Tolerance: Moderate drought; slight salt tolerance
 
Landscape Use Ideal for specimen planting, street tree use, and tropical borders. Works beautifully in civic landscapes, temple gardens, and butterfly gardens. Pairs well with Tabebuia aurea, Jacaranda mimosifolia, and Delonix regia for layered seasonal bloom.