SelecTree: Tree Detail
Photo Locations: Cal Poly State University - San Luis Obispo, CA, Lyon Arboretum - Honolulu, HI and Kona, HI
Koa is endemic to the Hawaiian Islands and makes one of the most valuable hardwoods in the world. Its wood was traditionally used for many applications, including musical instruments (ukuleles), surfboards, fishing hooks, and outrigger canoes. The young leaves are feathery and divided but quickly develop into single, curved, leathery simple leaves (called phyllodes). Many acacias, especially the species native to Australia and the Pacific Islands make leaves that mature into simple, undivided phyllodes. This is thought to be a drought adaptation. Koa is a large tree that can become nearly 100 feet tall in its native stands. Acacia koa has no HPWRA (Hawai'i Pacific Weed Risk Assessment) score, and the Plant Pono link is: https://plantpono.org/pono-plants/acacia-koa/
Native to Hawaii.
Erect or Spreading with a High Canopy.
Conical or Rounded Shape.
Has Evergreen foliage.
Height: 40 - 60 feet.
Width: 30 feet.
Growth Rate: 36 or More Inches per Year.
Longevity 50 to 150 years.
Leaves Lanceolate, Bluish Green or Silver or Gray Green, No Change, Evergreen.
Flowers Showy. Cream or Yellow. Flowers in Spring or Summer. Has perfect flowers (male and female parts in each flower).
Brown or Purple Legume, Very Large (Over 3.00 inches), fruiting in Winter or Summer.
Bark Black or Dark Brown, Fissured.
Shading Capacity Rated as Moderately Dense in Leaf.
Litter Issue is Dry Fruit.
Tree Site Conditions & Constraints
Sunset Zones H1, H2.
USDA Hardiness Zones 9 - 11.
Exposure Full Sun to Partial Shade.
Wet to Dry Soil.
Loam or Sand Texture.
Acidic / Neutral Soil pH.
Salinity Tolerance is Good Inland.
Seaside Tolerance is Good in Mild Zone.
Pests & Disease Information
Susceptible to Invasive Shot Hole Borer, Beetle Borers and Thrip, Phytophthora and Root Rot.
Health, Safety & Environmental Concerns
Branch Strength Rated as Weak.
Root Damage Potential Rated as High.
Allergy Health Hazard.
Biogenic Emissions considered Moderate.
Not Deer Palatable.
Special Uses & Values
Cite this tree:
SelecTree. "Acacia koa Tree Record." 1995-2021. Apr 17, 2021.
< https://selectree.calpoly.edu/tree-detail/acacia-koa >