Indigobush
Amorpha fruticosa
Washington State Classification
Class B — Control Required (Designated)
Although native to the Eastern United States, in some Western states it is considered invasive and has naturalized.
Required control in Region 1 (all western Washington counties)
Quick Reference
Identification
Growth Habit
Indigobush is a thornless, deciduous, multiple stem shrub that can grow to over 12 feet tall and can form thickets.
Leaves
Leaves are made up of 13 - 25 leaflets which are one to two inches long. They are gland dotted and hairy with smooth margins.
Flowers
Flowers are in dense, upright clusters, in the upper branches. They are blue-violet to dark purple and have 10 stamens.
Fruit & Seeds
Seed pods are small, curved, dark brown, about 1/4 inch in size and are dotted with glands. Each pod contains 1 or 2 seeds.
Impact
Although native to the Eastern United States, in some Western states it is considered invasive and has naturalized. It escapes planted areas and grows along streams and rivers and prairie draws forming dense thickets and outcompetes native species.
Ecology & Spread
Habitat
Indigobush grows in prairies, hillsides, sandy roadsides, along streams and rivers. Please click here to see a county level distribution map of indigobush in Washington.
Spread Mechanisms
Reproduction
Indigobush reproduces by seed.
"
Control Methods
Mechanical
- Cutting plants may result in re-sprouting stems. Repeated cutting may be used to control seed production each year.