Tropical Gardening: Rare palms abound in Hawaii gardens

Courtesy of VOLTAIRE MOISE Many native specimens of loulu palms can be found in the Amy B.H. Greenwell Ethnobotanical Garden in Kona. Several are seeding, and the palms can be propagated from seeds collected before pigs and rats eat them.
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Are you interested in conservation? How about learning more when it comes to Hawaiian palms?

We have at least 24 species of endemic Pritchardia, or loulu, all of which are endangered and could become extinct without our help. Then there are thousands of palm species worldwide that are endangered because of habitat loss.

Many have been introduced to Hawaii by our botanical gardens, nurseries such as Jeff Marcus’ Floribunda Palms and the International Palm Society. In fact, we probably have more palm species here than any other place in the nation.

The good news is that our Hawaii Island Palm Society is anxious to share rare species with those interested by inviting local folks to join it and the International Palm Society.

By joining the International Palm Society, the whole world of palms is open to you. Every two years it sponsors an educational trip to exotic locations.

In 2020, the group will be heading to the remote island of Reunion in the Indian Ocean and Madagascar. For more information, visit internationalpalmsociety.com.

Hawaiian Pritchardias actually evolved here and are found growing naturally only in Hawaii. At one time, there might have been many dozens of species, but with the introduction of the Polynesian rat and pig, many must have died out. Later introduction of grazing animals did further damage so now there are only remnants of what must have been vast populations of loulu.

Of some 28 species of Pritchardia in the world, 24 are natives of Hawaii. The remainders are found on a few islands in the South Pacific. Two new South Pacific species were only recently discovered. It is a shame that many of these species declined in number to the point they are almost extinct.

For example, the Kona loulu, or Pritchardia maideniana, is a tree from Puna, Kona and Ka‘u. These palms were at one time found abundantly from Kalapana along the coast to Punaluu and the Kailua area of Kona, a distance of more than 150 miles. Today, only occasional isolated specimens can be found. Few seedlings appear around the parent plants. Without man’s help, they, too, will disappear.

Pritchardia maideniana is rarely found in the wild and only occasionally in the landscape. The most common types are two introduced species from the South Pacific. These are Pritchardia thurstonii and Pritchardia pacifica.

Thurston’s loulu is noted for flower clusters up to 6 feet long. Pritchardia pacifica has very large leaves that were used in the old days as sunshades and umbrellas.

These species are adapted to dry coastal locations. Pritchardia maideniana prefers sunny, drier locations but has been grown at elevations as high as 3,000 feet.

Another rare one is named after George Schattauer, Kona kamaaina. A few trees are found above Kaohe, Honomalino and Hookena. This species and Pritchardia beccariana from Kulani prison road near Volcano are being distributed on the Big Island.

It’s important to the survival of many of these beautiful species to use them in our gardens. Unfortunately, many nurseries do not carry the native loulu, and seed of some species are difficult to obtain. Amy B.H. Greenwell Ethnobotanical Garden has a good collection of species. If interested in obtaining seed, contact the garden.

To propagate loulu palms, plant fresh seeds in flats or shallow boxes filled with soil. Cover the seeds with from 1/8 to 1 inch of soil, depending on the size of the seed. Keep the soil in the flats moist but not wet. Damping off fungi are likely to ravage the tiny seedlings if the soil is kept soggy.

Seed flats can be covered with clear plastic to keep in warmth and moisture. This will speed up germination. Be sure to keep seed and seedlings protected from rats.

Germination time of palm seed varies widely with the species and requires patience. They might not peek out of the ground for several months following planting.

Pot the plants into 1-gallon containers after they sprouted. A suggested potting mixture is equal parts of soil or cinder and rotted compost. Fertilize monthly with a complete fertilizer.

When the seedlings are 1-2 feet high, transplant them to 3-gallon containers or plant them in the ground. Loulu palms are well suited for planting in groups, as specimens or for lining driveways. Young palms require coddling until established. Then they thrive with very little attention other than sun, fertilizer and water.

Remember, if folks begin to show interest in rare plants such as the Hawaiian Pritchardias, our nurseries can then afford to carry them as part of their regular stock. These palms and many other native plants should be used in the Hawaii landscape. It is up to us to make it happen.

For more information about gardening, contact the UH College of Tropical Agriculture and Human Resources Master Gardeners at 322-4893 in Kona or 981-9155 in Hilo.