This Month in the Garden: A Visit to the Keahua Arboretum, Kauai-Rainbow Eucalyptus Forest

Keahua Arboretum, Kauai

As an avid gardener, I will seize every opportunity to travel beyond the northeast to explore gardens and plants I have never seen before. I recently had the pleasure of visiting the Keahua Arboretum on the island of Kauai to see the most amazing Rainbow Eucalyptus trees I have ever experienced. Resembling multi-colored pieces of living artwork, these trees have a rich history.

Keahua Arboretum, Kauai

The Keahua Arboretum is located at the end of the scenic Kuamoo Road (Highway 580) on the island of Kauai, Hawaii. It was planted with native and introduced plants by the University of Hawaii to be used as an outdoor classroom for students and visitors. It is here that the Kuilau Ridge Trail starts and the 1.5 mile portion of the Na Ala Hele Trail System turns into the Moalepe Trail, leading though groves of eucalyptus forest, native shrubs and vines to give visitors a spectacular view. 

Rainbow eucalyptus (Eucalyptus deglupta

Rainbow eucalyptus (Eucalyptus deglupta) is a large tree native to Indonesia, Papua New Guinea, and the Philippines, and is the only Eucalyptus species with a natural range that extends into the northern hemisphere. Hardy in USDA zones 10 and above, it is characterized by multi-colored peeling bark displaying hues of orange, maroon, blue, purple and gray. Patches of outer bark are shed annually at different times, showing a bright green inner bark. The inner bark then darkens and matures to produce the blue, purple, orange and then maroon tones. The process continues as the previous season’s bark peels off in strips to reveal a brightly colored new bark below. Rainbow eucalyptus thrives in rich, medium to wet soil in full sun, is intolerant of frost and grows to 250 feet in height in its native habitat. Every tree is unique with its own configuration of color.

Rainbow eucalyptus

The first to discover medicinal uses of eucalyptus were the Australian aboriginal populations. Eucalyptus had been discovered to have antibacterial properties early on and towards the end of the 19th century, it was used in English hospitals as a disinfectant. Eucalyptus has also been found to promote oral health. In studies, participants who regularly chewed gum with eucalyptus extract had lowered levels of plaque accumulation and overall healthier gums. Eucalyptus can also help to provide relief from coughs and colds and is found as a common ingredient in many cough syrups, rubs and vapor baths. Findings also suggest that eucalyptus can be used as an ointment for sore muscles. Other uses of eucalyptus included use of the wood by Australian aboriginals to make tools and weapons, while today the wood is mainly used for the manufacture of paper and furniture. Eucalyptus leaves are also used to create essential oils for aromatherapy and the aroma of its oils can help act as a natural insect repellent.

Island Gecko (Phelsuma) on eucalyptus tree.

Map of Līhu‘e-Kōloa Forest Reserve (Courtesy of Department of Land and Natural Resources)

Rainbow eucalyptus

Once through the eucalyptus forest, the Keahua Arboretum leads access to the Līhu‘e-Kōloa Forest Reserve, an area consisting of over 12,500 acres of public land in two separate areas, Wailua and Kalāheo. The area was established by the Governor’s Proclamation in 1909 for the purpose of protecting the vital watershed area. The reserve has an elevation of 1699 feet (518 meters) and has is the home of numerous hiking trails. 

For more information visit Keahua Arboretum.

Be sure to stop by on the 1st. of each month for This Month in the Garden, as I share gardening tips, information and horticultural adventures! Linking with:  Floral Fridays, Macro Monday 2, Friday Photo Journal, Image-in-ing Weekly Photo Link-Up and Dishing It & Digging It, Our World Tuesday and Wednesdays at My Corner of the World.

~As Always...Happy Gardening! ~

Author: Lee@A Guide to Northeastern Gardening,© Copyright 2010-2019. All rights reserved.