Rainbow Shower Tree

Shade Trees

Hawaii

121 cities

The Rainbow Shower Tree (Cassia x nealiae) is a hybrid between the Golden Shower (Cassia fistula) and the Pink and White Shower (Cassia javanica), and no two trees produce exactly the same color combination. Flowers range from creamy white to soft pink to deep orange-yellow, often all on the same tree at the same time. In Honolulu's streets and yards, it's the tree people stop their cars to photograph in late spring and summer.

Lifespan

Typically 50 to 100 years with good structural pruning and drainage. Trees neglected for decades can become hazardous well before that.

Mature Size

Usually 25 to 40 feet tall with a canopy spread of 30 to 50 feet. In open yards with no competition, older trees can get considerably wider than they are tall.

Care & Maintenance

This tree wants full sun and well-drained soil. It's quite drought tolerant once established, so most homeowners actually overwater it, which is the faster way to kill it. A light balanced fertilizer once or twice a year is plenty. It thrives in Hawaii's climate with minimal intervention once it's settled in.

Common Issues & Threats

Orange sulphur butterfly caterpillars (Phoebis agarithe): These caterpillars specifically target Cassia species and can strip young foliage fast. You'll notice chewed leaflets and a sudden population of orange butterflies nearby. On an established tree this rarely causes lasting harm, but it can stress a young tree.
Root rot from poor drainage: Rainbow Shower does not tolerate wet feet. If you're planting near a lawn that gets heavy irrigation, or in a low spot that holds water, the roots will rot before you realize there's a problem. Yellowing leaves and branch dieback starting at the tips are the early signs.
Brittle branch structure: The wood is not particularly strong, and older trees with poor structure can drop significant limbs in high winds. This is a maintenance issue, not a disease, but it's the one that causes property damage.

Pruning Guide

Prune right after the main flowering period ends, typically late summer into fall in Hawaii. The goal is structural, not cosmetic. Remove crossing branches, anything growing back toward the center of the canopy, and dead wood. Here's what most people get wrong: they shear this tree into a round ball shape, which destroys the natural branching and actually increases the chance of wind damage later.

Did You Know?

Because Rainbow Shower is a hybrid, seeds from your tree will not grow into a tree that looks like yours. The only way to reliably propagate a specific color form is through grafting, which is why certain prize-winning color forms are genuinely rare. Your tree's particular combination of colors is essentially unique.

Where Rainbow Shower Tree Is Found

Rainbow Shower Tree is common in 121 of the US communities we cover, across 1 climate regions.

Hardiness Zones 1

East Honolulu, HI Zone 12b Hilo, HI Zone 11a Pearl City, HI Zone 12a Kailua CDP (Honolulu County), HI Zone 12b Waipahu, HI Zone 12b Kaneohe, HI Zone 12b Mililani Town, HI Zone 12a Kahului, HI Zone 12b Ewa Gentry, HI Zone 12b Kapolei, HI Zone 12b Kihei, HI Zone 12b Mililani Mauka, HI Zone 12a

... and 109 more cities

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