Scientific Name: Bidens amplectans; B. menziesii; B. torta
Description: Small shrubs usually 3 to 4 feet tall with dark green serrated leaves and many bright yellow flowers. The flower of this species is unique compared with other native species within the same genus.
For one, they are very large, usually 3 to 4 inches in diameter. Most other species in the genus (with the exception of B. cosmoides and B. valida) have smaller flowers. Second, the flowers have a pleasant fragrance similar to that of carnations. I’m unaware of any other native Bidens that possess that type of fragrance, if any at all.
Distribution: This endemic plant is found only on the Mokuleia side of the Waianae Mountains on the island of Oahu, usually on rocky cliffs either exposed to the sun or as an understory plant.
Cultural Uses: Like other ko’oko’olau, this species can also be used to make tea. Pick the fresh leaves (flowers are OK, too), wash them off and boil them in water. No need to dry the leaves first – fresh leaves are healthier and they taste better. Pick enough leaves and flowers to cover the surface of the water in whatever size pot you are using, and enjoy!
Landscape Uses and Care: This native Hawaiian plant is usually short-lived, lasting about one to two years, but will generally have new plants come up from fallen seeds. Because of its profuse bloom, it should be displayed in an area where it is easily visible, perhaps with a dark background like a rock wall or ti leaf hedge.
Few pests bother this plant, but other members of the genus are somewhat affected by mites and spittle bugs.
These should be treated either by spraying manually with water (soapy water is OK) or with an organic pesticide. Since this plant is used to make tea, don’t use any harsh chemicals, especially systemic pesticides, to treat for bugs. Daily watering is fine but not required, and full sun/partial shade is best.Kookoolau