Cassia × nealiae
rainbow shower tree
Cultivated hybrid; parent species native to South and Southeast Asia
Overview
Cassia x nealiae is a tropical flowering tree of hybrid origin between C. javanica and C. fistula, developed in Hawaii and grown widely in frost-free climates. It forms a spreading, rounded crown 30–40 feet (9–12 m) tall and nearly as wide, with pinnately compound leaves 8–16 inches (20–40 cm) long made up of paired oval leaflets. From late spring into summer the branches carry pendent and upright clusters of five-petalled flowers that open in shades of pink, apricot, cream, and yellow, often with several colours present on one tree at the same time. Individual clusters last about two weeks, and a tree may flower in waves over two to three months. As a sterile hybrid it sets few or no viable seed pods and is propagated by grafting or air layering rather than seed. The tree needs heat and full sun, drops some leaves in cool or dry periods, and is killed by frost, surviving only in USDA zones 10–11. The wood is somewhat brittle and large limbs can split in high wind. Surface roots can lift nearby paving over time.
Native Range
The tree is a cultivated hybrid first selected in Honolulu and has no natural wild range. Its parent species are native to South and Southeast Asia.Suggested Uses
Planted as a street, park, and large-garden shade tree in tropical and subtropical regions, spaced 25–35 feet (7.5–10.5 m) apart. Also used as a flowering specimen where its mixed-colour bloom suits open lawns.How to Identify
Appearance
Size & Dimensions
Height30' - 40'
Width/Spread30' - 40'
Bloom Information
Flowering runs from late spring into late summer, mainly June through August in Hawaii. Clusters open in successive waves over two to three months, with several flower colours often present at once. Each cluster lasts roughly two weeks before petals drop.
Detailed Descriptions
Flower Description
Pink, apricot, cream, and yellowFoliage Description
GreenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grows in full sun on deep, well-drained soil with a pH from 6.0 to 7.5 and needs ample warmth for strong flowering. Tolerates short dry spells once established but flowers most heavily with regular water through the growing season. Young trees are staked and trained to a single leader because the wood is brittle and prone to splitting. Frost kills the tree, restricting it to USDA zones 10–11 and frost-free coastal subtropics. Propagation is by grafting or air layering, as the hybrid sets little viable seed.Pruning
Structural pruning of young trees in the dry season builds a strong branch framework and reduces later limb splitting. Crossing and weak branches are removed after flowering. Mature trees need only the removal of dead or damaged wood.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
summer