ko’oko’olau (Bidens spp.) is a medicinal native Hawaiian plant. The two species I will describe are Bidens menziseii subsp. filiformis, and Bidens hawaiensis, both endemic to Hawaii Island. There are over 200 species of Bidens worldwide, with many of them being highly medicinal. Medicinal properties include: promotion of good health, cleanse the body, prevents: strokes, diabetes, constipation, stomach, and liver problems. Basically good for everything, do some more research to identify more medicinal properties. This plant is also highly ornamental!
ko’oko’olau grows well from seed or cuttings. I prefer to grow them from seed so they have a stronger root system, as they tend to fall over when they get large.
Surface sow seeds and they should germinate within two weeks.
It would be safe to call ko’oko’olau a weed, as it propagates readily and grows quickly. Needing no care at all. I have noticed ants love farming on menziseii but it doesn’t seem to affect them.
They prefer full sun but will grow in part shade. These two varieties grow from the coastline to about 8000’. And need good drainage, meaning add lots of cinder into the soil mix. Or grow them on straight cinder or straight lava like they grow in the wild!
Did I mention they are frost, drought, heavy rain, scorching sun, and high winds tolerant? Yeah, grow ko’oko’olau anywhere and everywhere!!
Bidens menziseii subsp. filiformis grows to about 15’ with the largest trunk diameter I’ve seen is over 5 inches!
Bidens hawaiensis grows to about 6’ in a more shrub like habit.
Grab a few leaves and throw them in boiling water. You could also dry the leaves first, 3 cups water to 1 tablespoon of dried leaves.
Where to obtain planting materials
I highly recommend sourcing seeds or cuttings from your local species as the islands of Hawaii contain 19 endemic species. Please grow the correct species, as keeping genetics pure will allow these species to continue to thrive in their endemic habitat. As some of these species are rare, it would be wonderful to promote and propagate them in the correct environment and hopefully seeds will spread and become more naturalized and hopefully spread from cultivated specimens and retake their landscapes.
If you live in puna contact me for a seed source. I will share when they are in season.
I first learned of Bidens menziesii while working on Mauna Kea replanting the high elevation forest. Working closely with this plant gave me an appreciation of this species. On the mountain this seems to be the fastest growing species, making it the pioneer plant the mountain needs to become reforested once again. This is a keystone species that we plant with Sandalwood, as the host plant. This plant also goes to seed within half a year and sets seed vigorously. Perfect for a restoration plant. In the forest at home this plant grows well, but has not flowered yet. Possibly due to the amount of shade it receives.
I’ve only been growing Bidens hawaiensis for a little while now and do not have quite as much experience with it. Although it has already flowered, I was not able to catch seeds because the rain knocked them off.