The exquisite 'ohai (Sesbania tomentosa) is the perfect native Hawaiian plant for your home garden when the environment is dry, hot and subject to salt spray.

The natural habitats for 'ohai are dry coastal shrublands and grasslands, or dry forests, although the latter is uncommon. 'Ohai will thrive on calcareous beaches and sand dunes, deep red soil, rocky slopes and ridges, and in soil pockets over lava. 'Ohai is the only endemic Hawaiian species in the genus and was federally listed as endangered on Nov. 10, 1994.

Approximately 28 scattered populations of 'ohai exist in Hawai'i, on federal, state and private land. There are an estimated 4,000 to 5,000 plants, but some groupings are reduced to only a few to 30 individuals. 'Ohai is established on all the major islands (except for Ni'ihau and Lana'i), and on the Northwestern Hawaiian Islands of Nihoa and Necker.

Primary threats to 'ohai in the wild are 1) habitat loss and degradation, 2) grazing and trampling by axis deer, cattle and goats, 3) seed predation by rats, 4) invasive weeds and grasses, 5) fire and 6) destruction by off-road vehicles.

'Ohai is usually an erect or prostrate sprawling shrub, with horizontal or arching branches, but sometimes grows to a small tree. Each compound leaf, with numerous oval leaflets, is covered with silky, silver hairs. Its pea-shaped flowers are found in clusters of two to nine, and are salmon colored with yellow, scarlet, or orange-red tinges, or rarely, pure yellow. Its fruits are slightly flattened pods, with about six to 27 olive, pale brown or dark brown oblong seeds. The plant was first described by W. J. Hooker and G.A.W. Arnott in 1836 from collections made on O'ahu.

Hawaiians used the flowers and seeds of 'ohai in crafting stunning leis. (Find page 109 of the book, "Na Lei Makamae," for a gorgeous example of an 'ohai lei.)

When propagating 'ohai, manually remove seeds from the pod. Seeds can be stored for several years if kept dry and cool.

Before planting, scarify (penetrating the seed coat) the seeds with a clipper, file, or sandpaper, then soak the scarified seeds in room temperature/warm water for a few hours or overnight. Discard any seeds that float, then plant the rest in sterile, well-draining potting mix (two parts perlite to one part vermiculite to one part washed beach sand). Germination takes about a week. After sprouting, transplant 'ohai into 4-inch pots, and place in the shade for a week before moving plants into full sun. Outplant in three to six months. 'Ohai plants desire full sun and a well-drained location. Black twig borers, and occasionally root-knot nematodes and ants are problematic.

'Ohai is wonderful for sand stabilization and erosion control.

It is also excellent for beachfront landscaping. When planted in sandy, fast-draining, low-fertility soil, the plants flourish with intense sunlight and front brisk trade winds and salt spray. The variation in flower color and size offers tremendous potential as an ornamental plant. Incorporate 'ohai as a trailer on a rock wall, as a high ground cover, in an elevated planter bed or simply display it in a hanging container.

'Ohai is a native Hawaiian plant that deserves to shine under our Hawaiian sun and set roots in our Hawaiian soil.

Duane Choy is a consultant for nonprofit organizations involved primarily with environmental missions, and is a Hawai'i native-plant specialist. Reach him at hanahou@ecologyfund.net.