Koko Gardens:  One of the less known hiking trails on Ohau is the Koko Gardens.  This area has so many different kinds of plants and vegetation and is a quiet place to spend the day.  Some of the many plants found are:

Of special note is the native grove of wiliwili trees (Erythrina sandwicensis) found in the Hawaiian section.

KOKO CRATER BOTANICAL GARDEN is home to a collection of rare and beautiful plants from the tropical regions of the world. Some are rare or endangered in their native habitat.  It is a cinder cone remaining from the last active volcano that occurred on O'ahu approximately 10,000 years ago. This crater is the tallest tuff ring in Hawaii, measuring 1,207 feet in height. The slopes of the crater drop steeply into the Molokai Channel, an area which lacks protection from any offshore reefs, causing very turbulent seas in this area.

We have never seen so many different nor such large Cacti.  They grow in one whole section that is amazing both in the variety of plants and their individual size.  This collection is amazing.  This is a little known treasure on the island.  From our experience, this park has few visitors and is one of the island's best kept secrets.