Santalum haleakalae aka Haleakala Sandalwood

Santalum haleakalae is a shrub or small tree that stays green year-round. Its common name is Haleakala sandalwood. It is native to Hawaii and belongs to the sandalwood family, Santalaceae. Sources differ on which islands it grows on. Useful Tropical Plants lists only Maui. Plants For A Future lists Maui, Lana‘i, and Moloka‘i. It grows in patches of shrubland high in the mountains. Some sites have dry slopes that get moisture from fog.

The plant grows slowly and forms a dense, bushy crown. It often has several main stems, not just one trunk. Its reported height is about 7–13 feet [2–4 metres]. The crown can grow about as wide as the plant is tall. One garden listing gives both sizes as 10 feet [3 metres]. The trunk may reach about 8 inches [0.2 metres] across. It is a root hemi-parasite: it takes water and nutrients from nearby host plants. Growth is poor without a host that suits its needs.

Bees and other insects carry pollen between the flowers. People can eat the seeds, but seeds are scarce. They have greater value for growing new plants. Fresh seed soon loses its power to sprout. Growers therefore need to sow it soon. A small nick in the seed coat can help it sprout. Take care not to harm the embryo inside. Nursery plants can share a pot with a host. Growers give young plants more light as they grow. They do this before planting them out.

Give the plant some side shade but little shade from above. Deep shade causes poor growth. Full sun can suit plants linked to a suitable host. Light or medium soil that drains well suits it best. It can also grow in shallow soil or soil with few nutrients. It prefers soil close to neutral or slightly alkaline. It can cope with more acid soil too. Plants For A Future reports that it tolerates drought. It also lists USDA zones 9–12. Frost and long dry spells can occur in its mountain home.

Some Hawaiian gardeners grow it as a tree for its looks. Its scented heartwood gives oil for perfumes, cosmetics, and incense. Past uses include scented body oil and cloth. People used leaf washes to treat dandruff and head lice. They also used wood mixtures as medicine. These reports do not prove that such uses are safe or work. The sources report no known hazards. This does not prove the plant is free of toxic effects. Useful Tropical Plants cites a 2013 IUCN assessment. That assessment lists the plant as Vulnerable.