Tropical Gardening: Our state tree is the kukui, or should it be the loulu palm?

  • Photo courtesy of VOLTAIRE MOISE

    Pritchardia thurstonii growing on coral rock in the Lau Islands of Fiji. This species is popular in Hawaii, where it grows in rocky soils exposed to salty, windy or dry locations.

If you are truly interested in conservation, then choose to protect one of our most unique plant species, the genus Pritchardia.

If you think coconut palms, kukui, bananas, taro and ti are natives and seem to grow easily, then it is time to rethink! These plants are alien, non-native species brought to Hawaii by the Polynesians as they migrated across southeast Asia and the Pacific Ocean. These are referred to as canoe plants.

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For example, our state tree, the kukui, is thought to have originated in what is now Indonesia. Our state tree probably should be the Loulu palm genus because it is endemic to Hawaii.

Of course there are exceptions. Four species are found in the South Pacific; two were only recently discovered.

The Hawaiian loulus 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 perished. Later introduction of grazing animals did further damage so that now there are only remnants of what must have been vast populations of the loulu.

The native loulu group, or Pritchardia palms, are truly a vanishing species in Hawaii. Of some 28 species of Pritchardia in the world, 24 are natives of Hawaii. The others are found in Fiji and the Tuamotos.

It is a shame that many of these species declined in number to the point that they are almost extinct. It’s suspected that there might have been other species present on other Pacific islands, but have probably disappeared as humans with pigs and rats migrated though out the Pacific thousands of years ago.

The Kona loulu, or Pritchardia affinis 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, 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.

Another species, Pritchardia schattaueri, also might have been common at one time in upland areas of leeward Hawaii, but was reduced to just a few trees near Honomalino when identified as a new species late in the 20th century.

Otto and Isa Degner published an article in June 1971 in “Phytologia” Vol. 21 that speculates as to why the decline.

They wrote that on the island of Hawaii at Kaliilii, near Wahaula, within Hawaii Volcanoes National Park, a few impressions of prostrate trunks can be seen on a prehistoric, though not very old, pahoehoe lava flow. Beyond the southwestern boundary of the national park between the main road and the ocean, at Kawaa, lies an expanse of prehistoric, smooth pahoehoe.

Here, the pahoehoe had gently flowed through a palm grove, the wet trunks burning slowly through the base so the trees fell helter-skelter upon the cooling lava.

The writers are convinced that the loulu reached the Hawaiian Islands some eons ago and might have more or less encircled many stretches of the islands with extensive groves, particularly before the Polynesians brought the pig and perhaps, as a stowaway, the seed eating Polynesian rat. The fossil impressions at Kaliilii and above all at Kawaa are irrefutable proof of this fact.

By 1969, the Kona loulu was close to extinction along the Ka‘u coastline. Fortunately, C. Brewer and Co. Ltd., the major landholder in Ka‘u, just embarked on a resort development in the region and was developing a large nursery to supply materials for landscaping the project.

The company was interested in locating and propagating plants adaptable to this dry, windy region. It was thought that the native plants of the region should have first consideration since they proved their worth under Ka‘u’s climatic conditions.

In 1970, seeds of this palm were collected at the Beamer home adjacent to Punaluu Black Sand Beach. The seeds were planted in flats and grown to landscape size. Today, several groves are beautifying the Punaluu area. Trees from this batch of seed also found their way to the King Kamehameha Hotel, Kona Outdoor Circle garden and many other sites around the island.

Seeds distributed by the Hawaii Island Palm Society to California and even southern France and Morocco have been found to do well in protected locations.

Pritchardia affinis/maideniana is rarely found in the wild and only occasionally in the landscape. The most common types of Pritchardia are the 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. The Kona loulu prefers sunny, drier locations but has been grown at elevations as high as 3,000 feet.

The other 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 Road near Volcano are being distributed on the Big Island.

The latter is a spectacular rain forest palm with leaves almost 6 feet across. It prefers moist locations with wind protection.

Many species have been tested at Kona Cloud Forest Sanctuary in Kaloko Mauka and at Amy Greenwell Ethnobotanical Garden.

It’s important to the survival of many of these beautiful species to use them in our gardens. Unfortunately, most nurseries do not carry the native loulus, and seeds of some species are difficult to obtain.

To propagate loulus, 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 sprout. A suggested potting mixture is equal parts soil or cinder and rotted compost. Fertilize monthly with a complete fertilizer.

When the seedlings are 1-2 feet high, transplant them to 5-gallon containers or plant them in the ground. Loulu palms are well suited for planting in groups 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 more interest in native trees such as the loulu, our nurseries can then afford to carry them as part of their regular stock.

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County and state buildings and roadways are ideal for loulus since they do not have aggressive root systems. With the Queen Kaahumanu Highway widening project from the Kona airport to Kailua-Kona, wouldn’t it be great to see the median strip landscaped with native loulu palms, kamani, naupaka and other natives?

These palms and many other native plants should be used instead of grass that requires much more maintenance and water.