In the Garden
PO'OLA NUI
HUI KU MAOLI OLA
Latin name: Bidens cosmoides Many of us are familiar with the weed called Spanish needle or beggar's tick (Bidens pilosa). If you're not familiar with the name, you'll know it as the one with the little dark brown seeds and two barbs at the end that get stuck in our shoes, socks, pants, everything.Those barbs are an adaptation for the plant and act as its dispersal mechanism. Those barbs hook onto large grazing mammals like cows or deer and they then carry the seeds to different places. Here in Hawaii, we never had large grazing mammals to disperse seeds, so the plants had to adapt. Rather than having barbed seeds, the Hawaiian Bidens' seeds became twisted, curved or were more flattened out, all of which are better adaptations for wind dispersal.
Like other species of Bidens (Ko'oko'olau), the leaves and flowers of po'ola nui can be made into a tea. Hint: Pick fresh leaves and flowers, wash, then brew. Gather enough to cover the surface of the water in whatever pot you use, then steam to desired darkness.
Description: A crawling shrub up to 4 feet tall with dark green serrated leaves and bright yellow flowers that hang inverted to the stem. Compared with flowers from other native members (Ko'oko'olau) of the same genus, this species has the largest. Flowers from this plant may be up to 3 inches in diameter, while other flowers from different species may only be one-half to 1 inch across. It is believed that due to its large flower size, this particular species of Bidens is pollinated by native birds, whereas other species with smaller flowers are pollinated by insects or the wind.
Distribution: Naturally, this plant is only found in mesic forests of Kauai, but they are much less common today.
Landscape use and care: This plant does well in partial shade but will also do OK in full sun. Well-drained soil with organic amendments also is recommended. Daily watering is fine, but a good soaking every two days is better. This plant is not easily available, so if you are able to find one, put it in a place where you can easily show off those spectacular flowers.
Rick Barboza co-owns Hui Ku Maoli Ola, a native Hawaiian plant nursery, with Matt Schirman. "In the Garden" is a Friday feature about flora written by field experts. Gardening Calendar
In the Garden runs Fridays in Today.
