Hawaiian Names with Diacritics
- Waianae kookoolau
Endangered Species Status
Plant Form / Growth Habit
- Partially Woody / Shrub-like
Mature Size, Height (in feet)
- Herbaceous, Medium, 1-3
- Herbaceous, Tall, Greater than 3
Mature Size, Width
The width is fairly equal to the height of this species.
Short lived (Less than 5 years)
- Specimen Plant
Additional Landscape Use Information
As with all koʻokoʻolau, they can be grown in the herb garden for use.
This species apparently does not do well in containers and will slowly decline if not plant in the ground.
Source of Fragrance
- No Fragrance
Plant Produces Flowers
Additional Blooming Period and Fruiting Information
This is one of the larger flowered species. Ripe fruit, called achenes, are produced in the spring and summer. 
- Medium Green
Additional Pest & Disease Information
Spider mites, scale, mealybugs, spittlebugs, slugs, snails.
Organic fertilizers such as kelp or fish emulsion give excellent results. Unless you are growing your koʻokoʻolau for the leaves (used for herbal teas), be cautious of high nitrogen fertilizers which will produce an abundance of leaves but fewer flowers. [David Eickhoff, Native Plants Hawaiʻi]
Remove older brown leaves, which may not fall off immediately, for a cleaner landscape appearance. 
Additional Water Information
Water 2 to 3 times per week, until well established. Then decrease to 1 to 4 times per month. 
Soil must be well drained
- Full sun
- Partial sun
Space at least 5 to 6 feet to allow plants to spread to their full potential.
Though this species is reportedly drought tolerant, it appears to appreciate constant moisture, at least in pots. Perhaps the information suggests the "drought tolerance" for well established plants.
Special Growing Needs
Bidens amplectens should be repotted as the plant grows. If left in a small pot, plants become stunted and may not flower. 
Natural Zones (Elevation in feet, Rainfall in inches)
- Less than 150, 50 to 100 (Mesic)
Additional Habitat Information
Grows generally in dry areas. Restricted to the windward cliffs of the Northern Waiʻanae Range, Oahu.
Koʻokoʻolau (Bidens spp.) are members of the Aster or Sunflower family (Asteraceae). There are nineteen endemic species of Bidens.
The natives are not invasive as are some of the alien species such as kī (Bidens pilosa) with its harpoon-like seeds (kukū) that seem attracted to long pants, socks and shoe laces or the White beggarticks (Bidens alba) that blanket huge areas with "cute-but-don't-grow-them-anyway" white and yellow flowers.
The name Bidens is derived from the Latin bi, two, and dens, teeth in reference to the pappus awns or collective bristles on the achenes (fruit, seeds).
The Latin specific epithet amplectens means "stem-clasping (leaf base)." 
All Bidens species can hybridize, which should be avoided. Individual species are often restricted to one habitat.
Natural hybrids between Bidens amplectens and B. torta can be found where the two species intergrade from ear Kaʻena Point to at least the head of Mākua Valley on the summit ridge of the Waiʻanae Mountains between Kawaihāpai and Kaʻena Point, Oʻahu. Pure B. amplectens is restricted to the windward cliffs and crests.
This species is perennial and sometimes annual.
Early Hawaiian Use
Early Hawaiian used the leaves in hot teas and tonics. 
All species of koʻokoʻolau can be brewed as a tonic and each are said to have distinct flavors. Regarding Bidens spp., Isabella Abbott comments that "I find that the roughly half a dozen species common in Hawaiʻi offer two or three slightly different flavors, each a bit more subtle than commercial black tea." 
 "The Names of Plants" by David Gledhill, page 46.
 "A Native Hawaiian Garden" by John Culliney & Bruce Koebele, pages 95-96.
 "Lāʻau Hawaiʻi: Traditional Hawaiian Uses of Plants" by Isabella Aiona Abbott, page 102.
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