Family: Euphorbiaceae

Kukui is our state tree and is well known for its silvery-green foliage, which make them easily distinguishable from other plants along the valley. Young leaves are covered in grayish hairs, while older leaves mature to dark green. Leaves vary from 3- to 5-lobed. Kukui is monoecious, meaning having both male and female flowers on the same individual. However, most know kukui by its showy terminal clusters of small white 5-petaled male flowers. Few female inconspicuous flowers form near the flower cluster base. Pollinated female flowers will give rise to round green-brown stone fruits with leathery skin. Mature fruits will turn black containing 1-2 seeds within hard rough shells.

Habitat & Uses

Kukui is a hardy, beautiful, and useful lowland tree typically found in moist valleys and along streams and gulches. It is known to grow wild from sea level to 2200 feet throughout all of the islands. The kukui tree tends to be present wherever humans reside, but can also be found in Forest Reserves as it was commonly used to reforest large areas.

This Polynesian-Introduced plant is native to the Indo-Malaysia region, but the utility of this tree made it a staple canoe plant. Hāmākua was famous for its pākukui where groves of kukui provided essential agricultural mulch and nutrients required for kalo production. Hawaiians could craft lightweight canoes and fishnet floats from the soft white wood and they developed many uses for the kukui seeds as a single tree can produce 75-100 pounds annually. Shells were used in lei and dye for kākau (tattooing), kapa, and waʻa (canoes). Seeds could be roasted and used in torches, turned into the condiment ʻinamona, or spat into the ocean to see fish more clearly. Seed oils were used in lamps, paints, and fertilizers.

Although all parts of the kukui are toxic to humans and animals, Hawaiians were able to to transform the bark, flowers, and nuts into various traditional medicines. Such as using the purgative qualities of kukui nuts for constipation. Properly roasting kukui nuts seems to reduce danger, but eating too much of this rich nut will result in diarrhea. The inner bark provides a red-brown dye for kapa cloth and the white latex sap from the bark can strengthen kapa.

Landscaping & Cultivation

Kukui is a fast-growing tree that thrives in a variety of soil types – well drained, moist, slightly acidic to alkaline. It tolerates drought, salt-spray, wind, and heavy pruning. Kukui loves full sun and recently disturbed soils. This tree excels as a shade tree, screening/ windbreak, massed planting, and even in manicured lawns or landscaping as specimen trees. However, some people dislike the fruit litter with seeds that can readily germinate. Kukui also enjoys the company of shade-loving understory companions like palapalai, maile, ʻawapuhi kuahiwi, and māmaki.

Propagation is typically from seed or from volunteer seedlings under a mature tree, which can be easily transplanted. Untreated seeds in a consistently moist seedbed can result in high rates of germination after 5 months. To hasten the process, you can gently produce a crack on the kukui nuts and soak them in water overnight. Keeping kukui nuts in a bucket in full sun can also result in natural cracking of the shell over time.

Name Origins

The ʻōlelo Hawaiʻi kukui can mean the kukui tree or a torch. It is a symbol for enlightenment given its fire-sustaining oils and iconic silvery foliage in the forests. Hence the term kukui was also figuratively used for someone who is a guide or leader. Kukui is a kinolau (physical manifestation) of the pig deity Kamapuaʻa who helps to facilitate agricultural fertility. You can see the connection in kukui’s leaf shape, which resembles the face of a pig with its snout, ears, and sometimes tusks.

Plant Uses:

• Cultural significance
• Edible
• Lei flower
• Medicinal
• Privacy / screening
• Shade
• Specimen
• Windbreak
• Woodworking

Plant Dangers:

• Toxic to animals and humans