Water Erythrina sandwicensis thoroughly when the top few centimeters of soil feel dry. Allow the soil to dry out somewhat between waterings. Reduce watering significantly during cooler, dormant periods.

Avoid waterlogged conditions, which can lead to root rot.

Prune Erythrina sandwicensis to shape and maintain desired size, typically in late winter or early spring before new growth begins. Remove dead, damaged, or crossing branches.

Pruning can also encourage bushier growth and more flowering if done judiciously.

Propagate Erythrina sandwicensis from seeds, which should be scarified or soaked to improve germination. Cuttings can also be taken from semi-hardwood in summer, but seed propagation is more common.

Ensure good drainage for seedlings.

Repot Erythrina sandwicensis only when necessary, typically every 2-3 years, when the plant becomes root-bound. Use a well-draining potting mix.

Spring is the ideal time to repot, allowing the plant to establish before the peak growing season.