The Harold L. Lyon Arboretum sits at the mouth of Manoa Valley, managed by the University of Hawaii, and contains over 5,000 tropical plant species spread across 194 acres of steep, lush terrain. The arboretum specialises in Hawaiian native plants, ethnobotanical collections, and palms — the palm collection alone has hundreds of species from across the Pacific.
The trails through the arboretum connect with the lower end of the Manoa Falls trail, making it easy to combine both in a single morning. Walking through the garden in light rain — which is frequent in Manoa Valley — is particularly good, when the plant colours intensify and the forest sounds change. Free entry with a small parking fee. Open Monday through Saturday.