Koai’a is a small tree, 15 to 25 feet tall, from the dry leeward areas of Kaua'i, Maui, Moloka'i, Lana'i and Hawai'i. It is related to true Hawai'ian Koa but is smaller and more adapted to dry conditions. It has an attractive rounded shape and sickle-shaped, gray-green “leaves,” small yellow powder puff flowers, and brown seed pods.
Growing Native Hawai’ian Plants by Heidi Leianuenue Bornhorst