Koa
Acacia koa
Also known as: Koaoha
- Native to:
- Hawaii
Forest & Kim Starr (www.hear.org)
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Fabaceae
- Genus:
- Acacia
- Species:
- Acacia koa
- USDA Symbol:
- ACKO
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Tree
- Height:
- 3000 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Medium
- Bloom Months:
- jan,feb,mar,apr,may,jun,jul,aug,sep,oct,nov,dec
- Bloom Colors:
- yellow
Wildlife Benefits
- Butterflies & Moths:
- ★★★★★ Documented Lepidoptera association (GBIF)
- Caterpillars:
- ★★★★☆ Recorded caterpillar host plant (HOSTS Database)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★☆☆ Butterfly & moth species supported by this genus (NWF)
Garden & Ecology Notes
- Wildlife Value:
- birds, insects
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Mature trees are fire-resistant; seeds germinate well after fire due to reduced competition and increased light.
Soil Requirements
- Soil Type:
- fertile, well-drained volcanic soil
- pH:
- 5.0 - 6.5 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- Common in upland forests of Hawaii
Propagation & Germination
- Stratification:
- Warm stratification required — 30–60 days
- Scarification:
- Seed coat scarification required before sowing
- Germination Time:
- 14–30 days
- Notes:
- Seeds require scarification (nicking or hot water treatment) to break physical dormancy, followed by warm stratification.
Pre-treatment: Scarification is required. This can be done mechanically or with hot water treatment (195°F, 90°C) in a volume ratio of at least 5 parts water to one part seed for 1-3 minutes. Alternatively, sulfuric acid can be used, soaking time 10-60 minutes depending on seed size. In all cases, scarified seeds are soaked overnight to allow water to penetrate into the seed.
Establishment: Koa is native to the Hawaiian Islands. Found on all six major Hawaiian Islands: Hawaii, Molokai, Maui, Lanai, Oahu and Kauai. The largest and most thriving koa trees are found between 3000 and 6000 feet (915 and 1830 meters) elevation. Introduced pests and diseases limit their presence below 2000 feet. Genetic quality is a crucial aspect of koa performance and yield, and source must be carefully considered and matched for the outplanting site before seeds are collected.
Source: npn.rngr.net