Tranquil Ho'omaluhia Botanical Garden is located just off of Highway 83 at 45-680 Luluku Road in Kaneohe.  Originally built by the U.S. Army Corps of Engineers for flood protection, the 400-acre Botanical Garden... (with its 32-acre lake, nature trails, and picnic areas) offers an oasis today for those looking for a brief escape from Honolulu's urban distractions. Hoomaluhia Botanical Garden is located literally at the foot of the famous Koolau mountains.