Kou is a small to medium sized tree that grows 30-40 feet in height. It has large oval leaves that are round at the base and come to a point at the tip. Its large leaves make it a great shade tree. The bright orange flowers have no scent and grow in clusters on short stalks. The green fruit is round and changes to yellow and then to black.

Ancient Hawaiians had several uses for kou wood such as canoes, paddles, calabashes and boxes, even carved objects (such as dieties). The leaves were used to make brown dye for designs on kapa and the flower used for lei. In ancient legend kou was one of the first trees created.