The Polynesian-introduced kukui tree became the official tree for the State of Hawaii on Aug. 21, 1959, when Hawaii became the 50th state. Of all the wonderful heritage trees we have here, none is so grand nor has as many cultural uses as the kukui.
The tree grows quickly and can self–seed making it potentially invasive, but properly maintained it can be a lovely and very useful addition to a landscape. Its stately size, rounded spreading crown, seasonal inflorescence and silvery lobed leaves add a unique beauty to any property.
Adding to the appeal of growing kukui trees is the ease of maintaining them. Though they prefer a steady supply of water, they can tolerate lengthy dry periods. They have few pests and need only light pruning when young to ensure a desired canopy shape.
All parts of the plant were used by the early Hawaiians and many of these traditional uses are still practiced today. The light wood of kukui trees was often used for canoes and fishing floats. Kukui’s sticky sap is still highly regarded by Hawaiians as a healing covering for wounds or as an adhesive gum.
The leaves and the lightly fragrant white flowers are often used in lei, as are the inch-round nuts or seeds. The hard nuts can be rough sanded to reveal their natural grooves and gray or brown coloration. Today, they are often polished to a shiny black patina to make beautiful necklaces and bracelets.
The nuts were also burned traditionally to provide a dark coloring for body tattoos.
Historically, the oily nuts have also been burned and used like candles for indoor and outdoor lighting. The nuts were strung four or five on a stiff palm leaf mid-rib and the oil in them burned slowly and brightly providing an excellent portable light source. The oil is also known for its healing properties and is an important ingredient today in many creams and massage oils.
The nuts and oil of the kukui can be toxic in large doses, but small amounts provide a pleasant taste accent to many dishes. The oil is used to add flavor to salad dressings or sauted dishes and a tasty garnish called inamona is made by roasting and grinding up the nuts with salt. Caution is advised as the medicinal properties of the nut and oil include intestinal cleansing. A little is fine, too much can have a purging effect.
Sometimes called the varnish tree, the kukui nut oil has also been used to varnish and preserve wood as well as to waterproof fishing nets, tapa cloth and paper.
The inner bark makes a reddish-brown dye that is used for tapa cloth. The ancient practice of natural dye making called waihooluu is still taught and used. Bernice Akamine, a Hawaiian cultural arts practitioner, will hold a kukui dyeing workshop from 10 a.m. to 3 p.m. on Aug. 4 at Amy B.H. Greenwell Ethnobotanical Garden in Captain Cook.
Included in Akamine’s presentation will information on the many cultural uses of the kukui tree. The hands-on learning will include creating dyes from the kukui nut, the rind or outer husk of the nut as well as the bark and roots. Attendees will be encouraged to use the fabric provided to make swatches of the different dye colors created in the class. For those who want to apply their dyes to kapa cloth, some will be available for purchase in the garden’s gift shop. Wearing old clothes for this workshop is advised, especially while working with the dyes. For more details see the “gardening events” section.
With all these uses for the kukui tree as well as its aesthetic beauty, isn’t it time you planted one on your property? Trees are available at Amy B.H. Greenwell Ethnobotanical Garden as well as several local nurseries.
Tropical gardening helpline
Luana asks: Do you think it’s possible to grow wasabi here?
Tropical Gardener Advice: There are lots of “heres” here. The short answer is yes, we can grow wasabi successfully in some locations in Hawaii.
Wild wasabi (Wasabia japonica) grows in Japan along shaded wet stream banks in cool climates that range between 46 and 70 degrees. If you can imitate those conditions, you’ll have a jump on success.
One local success story began with a trained Master Gardener ordering wasabi root online. With overnight delivery, a single living root came to about $80. She planted it in a deep pot in fertile, fully composted soil with some water retention gel crystals added. She placed the pot in the shade and kept it well watered. It immediately sprouted leaves and within a few months it flowered and began to put out keiki roots. She now has 20 plants thriving in pots and expects to have some saleable roots of about 0.5 to 1 inch diameter in a few more months.
Under ideal conditions, planted wasabi rhizomes will put out stems that may grow to 2 feet long and a plant that may be 2 feet wide. The stiff and brittle stems are topped with round leaves. In a few months, the plant will flower and produce seeds. The seeds are very difficult to germinate in cultivation. Wasabi plants usually reach full maturity in about 24 months after growing a rhizome up to six or eight inches long and about an inch in diameter. When harvested, side roots are pulled off and used to start new plants.
Wasabi plants are grown successfully on several U.S. farms in the Pacific Northwest and in the mountainous areas of North Carolina. Washington State University has a very thorough publication on growing wasabi available online at cru.cahe.wsu.edu/CEPublications/pnw0605/pnw0605.pdf.
Not only is real wasabi, which we don’t often get in restaurants here, very tasty and potent, but it also has many health benefits, which are touted at several online sites.
Although growing wasabi here in Hawaii presents a challenge, it is possible and can have many rewards. Consider it and if you succeed, let us know how you did it.
The “Waihooluu: Kukui Dyes Workshop” will run from 10 a.m. to 3 p.m. at Amy B.H. Greenwell Ethnobotanical Garden in Captain Cook with Bernice Akamine. Registration is $45 general, $30 kamaaina and $25 for members of Bishop Museum or the garden. Advance registration required at 323-3318 or firstname.lastname@example.org.
Farmer direct markets: The Hooulu Community Market is held Wednesdays from 10 a.m. to 3 p.m. at the Outrigger Keauhou Beach Resort’s Royal Gardens; Keauhou Farm Bureau Market, 8 a.m. to noon Saturdays at Keauhou Shopping Center; and South Kona Green Market, 9 a.m. to 2 p.m. Sundays above Choice-Mart in Captain Cook
Plant advice lines are answered from 9 a.m. to 2 p.m. Thursdays at the South Kona cooperative extension service office, 322-4892. Questions may be submitted anytime to master gardeners at email@example.com or to the Kona Outdoor Circle at firstname.lastname@example.org.
E-mail plant questions to email@example.com for answers by Certified Master Gardeners. Some questions will be chosen for inclusion in this column.
Diana Duff is a plant adviser, educator and consultant with an organic farm in Captain Cook.