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Pittosporum hosmeri
Alternative Botanical Names
Pittosporum amplectens
Common Names
'A'awa hua kukui
Potential or Traditional Uses
Photo of Pittosporum hosmeri leaves and fruit
Pittosporum hosmeri is a small tree ranging in height from 10 to 25 feet. The bark is smooth and mottled light gray and brown. The upright branches are slender and stiff. The branches are generally smooth, but new growths and flower stems are densely covered with woolly, pale brown hairs.

The narrow, oblong leaves are somewhat leathery and range in size from 3 1/2 to 10 inches long and 3/4 to 2 3/4 inches wide. The veins are fairly prominent on the upper surface of the leaf and the lower surface is covered with white or pale brown hairs. The edges of the leaves are smooth and slightly rolled under. The ends of the leafs are pointed.

Pittosporum hosmeri has male and female flowers on separate plants so plants of both sexes are required for seed to form. The flower clusters contain 9 to 12 flowers and form either directly on the branches of the plant or from the base of the leaf stem. The cream-colored flowers are tubular and 1/4 to 1/2 inch long. The flowers are fragrant at night.

This Pittosporum is closely related to P. hawaiiense and, according to Wagner, they apparently hybridize when grown together. However, Culliney and Koebele observed that the fruits of P. hosmeri are ripe in the winter while P. hawaiiense fruits in the summer. (Culliney 1999; Lamb 1981; Wagner 1999; Weissich 1995)

Habitat and Geographic Range
Pittosporum hosmeri is an endemic tree found in damp to wet forests only on the island of Hawai'i. It grows at elevations ranging from 1,200 to 3,500 feet. It is most common on the leeward size of the island from the Kohala Mountains south to the Ka'u Forest Reserve at Mauna'anu. (Wagner 1999)
Propagation by Seeds
The fruits of Pittosporum hosmeri are cube-shaped capsules. These capsules are large and range in size from 1 to 3 inches long. They are fuzzy and brown when mature. The capsules open slowly to reveal the orange or red inner surface. Each capsule contains 40 to 45 seeds arranged in two rows within the capsule. The kidney-shaped seeds are range in color from black to reddish black. Each seed is 1/4 to 3/8 inch long. Fruits of Pittosporum hosmeri are generally ripe in the winter.

Woolliams reports that green fruit will often open if stored in a plastic bag. Koob noted that he has only has success with ripe fruit; he has been unsuccessful with both seeds from green fruit and with stored seeds. Culliney and Koebele found that viable seeds cannot be obtained from green fruit even when mature. Only fresh seed from newly opened ripe fruit germinated. Their procedure is to extract the seeds from the capsules and immerse them in a room temperature solution of 9 parts water to 1 part household bleach for 1/2 hour. After the seeds are removed from the bleach solution, they are soaked in tap water for a day using just enough water to cover the seeds. The seeds are sown on the surface of wet vermiculite in sterilized containers. The containers must have good drainage. The seeds are covered with a 1 inch layer of dampened green sphagnum moss. Culliney and Koebele found that Pittosporum seeds took many months to sprout. Koob reports sowing the seeds on the surface of peat-based soil-less potting mix which is kept moist, but not wet. In his experience, the first seeds take about 9 months to germinate, but all germinate within a month or so after the first ones.

Obata reports that Pittosporum species set very few seeds and that many seeds lack embryos. Artificial pollination did not result in additional viable seed. (Culliney 1999; Koob 2002; Lamb 1981; Obata 1997a; Obata 1997b; Wagner 1999; Woolliams 1976)

Propagation by Cuttings
There is no published information on successful cutting propagation of any Hawaiian Pittosporum species. Criley reports very low percentages in rooting tip cuttings using total auxin concentrations ranging from 4,000 parts per million (ppm) to 6,000 ppm under 30% shade with an intermittent mist system.

However, Adams obtained 100% rooting for the 3 cuttings he tried. These were 6 inch long semi-soft tip cuttings. They were treated with Greenlight talc containing 0.1% IBA. He used a rooting mixture of 1 part peat to 4 parts. The cuttings were rooted in a propagation structure with a clear Lexan roof using a misting system. The mist cycle was 30-45 seconds every 30 minutes. It took six weeks or more for the cuttings to root. (Adams 2003; Criley 1998; Criley 1999)

Propagation by Division
Not applicable.
Propagation by Air Layers
No information located to date.
Propagation by Grafting
No information located to date.
Propagation by Tissue Culture
No information located to date.
Adams, Pete. 2003. "Pittosporum rooting." Personal email. Posted 24 February 2003.

Criley, Richard A. 1998. Propagation of indigenous and endemic ornamental Hawaiian plants. Combined Proceedings of the International Plant Propagators' Society 48:669-674.

Criley, Richard A. 1999. Aloha Hawai'i. American Nurseryman 190 (3):50-61.

Culliney, John L., and Bruce P. Koebele. 1999. A native Hawaiian garden: how to grow and care for island plants. Honolulu: University of Hawai'i Press. p. 61-64.

Koob, Gregory A. 2002. "Ho'awa seed." E-mail. Posted 9 June 2002 to

Lamb, Samuel H. 1981. Native trees and shrubs of the Hawaiian Islands. Santa Fe, New Mexico: Sunstone Press. p. 43-44.

Obata, John K. 1997a. Common native Hawaiian plants worthy of cultivation. Newsletter of the Hawaiian Botanical Society 36 (3/4):74.

Obata, John K. 1997b. Growing native Hawaiian plants. Newsletter of the Hawaiian Botanical Society 36 (3/4):75-76.

Wagner, Warren L., Darrel R. Herbst, and S. H. Sohmer. 1999. Manual of the flowering plants of Hawai'i, rev. ed. 2 vols., Bishop Museum Special Publication 97. Honolulu: University of Hawaii Press and Bishop Museum Press. p. 1044-1045.

Weissich, Paul R. 1995. Hawaiian native plants in the landscape. Combined Proceedings International Plant Propagators' Society 44:332-335.

Woolliams, Keith R. 1976. The propagation of Hawaiian endangered species. NATO Conference Series. I, Ecology 1:73-83.

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The image in this record is used with permission from Dr. Gerald Carr's Web site "Hawaiian Native Plants" at
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Last updated:
17 October 2003

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