Tropical Gardening: Many plants from the Southern Hemisphere thrive in Hawaii

This Chambeyronia macrocarpa or red feather palm has become popular in Hawaiian landscapes. It is from New Caledonia and is noted for the new leaves that begin red and later turn green. (courtesy photo/Voltaire Moise)
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It seems bizarre that many plants from some of the most ancient geological regions of the world readily adapt to Hawaii’s young volcanic soils. Some in Hawaii are from Australia and ancient islands like Madagascar and New Caledonia. When it comes to strange animals and plants, Australia is in the lead for its share of the unusual to unique. This ancient mini continent has mammals that lay eggs to the marsupials that carry their premature babies in pouches. Recent fires put many in the animal kingdom at risk and the plant kingdom as well. Some Australian ecosystems will be altered for centuries and some may never recover.

Even though there are many species yet to be discovered, it is fortunate that some valuable plants have been introduced to our Islands before their extinction, Examples of palms that were thought to be extinct and then rediscovered are the Carpentaria and Wodyetia palms. Thanks to members of the International Palm Society, they are now popular landscape trees in tropical gardens around the world.

Some introductions have found Hawaii so inviting that we consider them weeds. A better definition for them could be pioneer species that are attempting to heal the wounds that humans and nature have created. The octopus tree (Schefflera actinophylla) and the silver oak (Grevillea robusta) are two examples. They tend to readily grow where the land is disturbed. If we were to be careful in protecting our native landscapes, trees like these would not be a problem. Be it as it may, let’s take a moment and forget their robust tendencies and appreciate them for their beauty. The silver oaks with their bizarre orange inflorescence may be seen in full flower along the Mamalahoa Highway in West Hawaii. Try to appreciate them from an artist’s perspective and recognize that they are like other trees, sequestering carbon and producing oxygen. Some woodworkers like Kim O. Christensen have recognized the value of silver oak for flooring and furniture. The old adage “One man’s meat is another man’s poison” might be appropriate here, but “Turning lemons into lemonade” might be better applied. Another example is that of the macadamia. When it was introduced to Hawaii, the nut was inferior, but UH researchers and farmers worked on selecting superior varieties to make it one of the best and expensive nuts on the market.

The Protea family is primarily found south of the equator in Africa, South America and Australia. It includes the genera Macadamia, Banksia, Grevillea, Hakea, Hicksbeachia and Stenocarpus. Of all the many floral choices available in the marketplace, none can beat the bizarre yet enhancing beauty of the Protea family. From the robust, intense-colored sunburst pincushion to the deceiving duchess that looks more like feathers than a flower, Proteas resemble no other flowers in the world. Even the common reforestation tree, silver oak (Grevillea robusta) has a striking inflorescence.

Silver oaks are often maligned because they tend to naturalize in abandoned pastureland, but one of the most colorful landscapes in West Hawaii and Ka‘u occurs in the spring when silver oak and jacaranda bloom.

Most Proteas require cool climates on the dryer side like Waimea, Volcano, West Hawaii, Ka‘u and Maui. They prefer well drained soils. When grown in wet or humid locations, disease and pests become a problem.

Even if you are not interested in growing Proteas commercially, you can be certain that these gorgeous and exotic flowers are perfect to enhance your home, garden or be a special, long lasting gift. If you receive some as a gift, remember that Proteas have another advantage besides their remarkable attractiveness. They can be easily dried and enjoyed for a long time to come. All you have to do is remove the water from the container when the flowers start to lose their freshness and allow the flowers to dry into a permanent arrangement.

Another method is to hang the flowers upside down for about a month, and then use them in a dry flower arrangement. To eliminate the possibility of mold setting in during drying, space the flowers out to allow a good circulation of air. This latter method is especially suited to types that have a tendency to bend over as they lose their freshness.

If you are not familiar with Protea group, ask your local florist to show you the various types now being produced, what each is called, and how long they will last. If you’re looking for something special, Proteas are worth checking out. Other long lasting floral gifts include dendrobium, cymbidium orchids, anthurium, bird of paradise, heliconia and other flowering Hawaiian exotics.

For further information on the Protea family, contact your local UH College of Tropical Agriculture Extension Service office. Master Gardeners there can help you with pertinent information. In Hilo the number is 981-5199 or call Kona 322-4893. Several books are available like Sunset’s Western Garden Book to give you tips on growing these amazing plants.

Norman Bezona is professor emeritus, University of Hawaii College of Tropical Agriculture and Human Resources.