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Indigo-bush

Amorpha fruticosa

Common names:
indigo-bush, indigobush, false-indigo, desert indigo-bush, indigo bush amorpha, bastard indigo

Content Detail

Indigo-bush is a medium to large, finely textured, native shrub for wet to dry soils. The 1 foot long, compound leaves are a gray-green. The long-blooming, showy, 3 to 6 inch long, upright flower spikes are royal purple with yellow-orange anthers. A cousin of the shorter prairie lead plant, this plant may be short-lived. This species is native to the Chicago Region according to Swink and Wilhelm’s Plants of the Chicago Region, with updates made according to current research.

  • Family (English) Pea
  • Family (botanic) Fabaceae
  • Tree or plant type Shrub
  • Foliage Deciduous (seasonally loses leaves)
  • Native locale Chicago area, Illinois, North America
  • Size range Medium shrub (5-8 feet), Large shrub (more than 8 feet)
  • Light exposure Full sun (6 hrs direct light daily), Partial sun / shade (4-6 hrs light daily)
  • Hardiness zones Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8, Zone 9
  • Soil preference Acid soil, Alkaline soil, Dry soil, Moist, Sandy soil, well-drained soil, Wet soil
  • Tolerances Alkaline soil, clay soil, Occasional drought, Occasional flooding, Road salt, Wet sites
  • Season of interest early spring, mid spring, late spring, early summer
  • Flower color and fragrance Blue, Purple
  • Shape or form Multi-stemmed, Open, Oval, Round, Thicket-forming, Upright
  • Growth rate Fast
  • Has cultivars No

Native geographic location and habitat: 

C-Value: 6. Native to the Midwest, it is found along flood plains, rivers, and stream banks. 

Attracts birds, pollinators, or wildlife: 

Birds and butterflies are attracted to its flowers.

Bark color and texture: 

The bark is gray to brown, slender, and twiggy.

Leaf or needle arrangement, size, shape, and texture: 

The alternate leaves are up to 1 foot long and compound, with oblong to oval shaped leaflets.

Flower arrangement, shape, and size: 

Tall, upright 3 to 6 inch long flower spikes are found at ends of branches. Individual flowers are royal purple with yellow-orange anthers. The flowering period is quite long.

Fruit, cone, nut, and seed descriptions: 

The fruit is a small, warty, kidney-shaped pod which persists into winter.

Plant care: 

A large, sparsely branched, rounded shrub reaching 8 to 15 feet high and 8 to 10 feet wide. It prefers moist soil in full sun, but is tolerant of dry sites once it is established. It transplants easily, but may be short-lived. The flowers form on new wood, so prune in late winter or early spring.

List of pests, diseases, and tolerances: 

Rust, powdery mildew, and stem cankers can be problems on this plant.

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