Sesbania tomentosa aka `Ohai

Sesbania tomentosa, called ohai, belongs to the pea family, Fabaceae. Its native range lies wholly within the Hawaiian Islands. It grows in a tropical climate with dry seasons. Once widespread in Hawaii's dry lowlands, it now has fewer wild sites. Useful Tropical Plants reports its IUCN status as endangered. Coastal building, off-road vehicles, cattle, and goats have helped damage its habitat. Plants have also escaped gardens and become established in Puerto Rico.

Ohai most often forms a low shrub with spreading branches. These branches may lie flat or curve above the ground. The source lists a height of about 3.3 feet [1 metre]. Yet the species varies greatly in shape and size. Upright, tree-like forms can reach 8.2–19.7 feet [2.5–6 metres]. Garden plants tend to stay below 9.8 feet [3 metres] across. Wild plants can spread across much larger areas. Their branches may exceed 46 feet [14 metres] in length.

Large flowers give this shrub its main garden appeal. Bees pollinate the flowers, and the plant is self-fertile. People use both flowers and seeds to make Hawaiian leis. Its low growth suits ground cover and coastal soil control. Gardeners can also grow it as a hedge. The supplied source lists no known food or medicinal uses. It reports no known hazards, but this does not establish food safety.

Give ohai full sun and light soil that drains well. It grows best in dry sites and withstands drought once established. It also tolerates salt spray and strong winds. Wild habitats include sandy beaches, dunes, and pockets of soil on lava. It also grows on rocky slopes and in dry shrubland. Some plants occur beside ponds or in dry forest. These records show its range of habitats, not a need for wet soil.

Ohai grows fast, but tall forms may need support. Wind can topple plants whose upper growth becomes too heavy. This risk increases where soft soil gives roots less support. Too much water or feed may drive that excess growth. The source singles out added nitrogen as a possible cause. Seeds have a hard coat that can slow germination. Scarification and soaking can help them take up water before sowing. No specific pests, diseases, bloom season, or cold limits appear in the supplied evidence.