SelecTree: Tree Detail

KOA
Acacia koa

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Photo Locations: Cal Poly State University - San Luis Obispo, CA, Lyon Arboretum - Honolulu, HI and Kona, HI

General Notes

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), surf boards, 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 (Hawaii Pacific Weed Risk Assessment) score, and the Plant Pono link is: https://plantpono.org/pono-plants/acacia-koa/

Native to Hawaii.

Family: Fabaceae

Synonyms

Acacia kauaiensis
Racosperma kauaiense

Tree Characteristics

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, Gray Green or Dark Green, No Change, Evergreen.

Flowers Showy. Cream to Yellow. Flowers in Spring or Summer. Has perfect flowers (male and female parts in each flower).

Brown or Purple Pod, 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.

Drought tolerant.

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.

Attracts Birds.

Not Deer Palatable.

Special Uses & Values

Pollarding.

Cite this tree:
SelecTree. "Acacia koa Tree Record." 1995-2020. Apr 6, 2020.
< https://selectree.calpoly.edu/tree-detail/acacia-koa >

This tree is not part of the SelecTree Nursery Connection. If you would like to see this tree listed, or know of a nursery that sells it, please contact us at ufei@calpoly.edu.