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Leaves and fruit of indigo-bush.

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. Plants 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."   

Botanical name:

Amorpha fruticosa

All common names:

indigo-bush; indigobush; false-indigo; desert indigo-bush; indigo bush amorpha; bastard indigo

Family (English):


Family (Botanic):


Tree or Plant Type:

  • Shrub

Native Locale:

  • Chicago area,
  • Illinois,
  • North America

Landscape Uses:

  • Massing,
  • Mixed border,
  • Specimen

Size Range:

  • Large shrub (more than 8 feet),
  • Medium shrub (5-8 feet)

Light Exposure:

  • Full sun (6 hrs direct light daily),
  • Partial sun/shade (4-6 hrs light daily)

Hardiness Zones:

  • Zone 4,
  • Zone 5 (Chicago),
  • Zone 6,
  • Zone 7,
  • Zone 8,
  • Zone 9

Soil Preference:

  • Acid soil,
  • Alkaline soil,
  • Dry soil,
  • Moist, well-drained soil,
  • Sandy soil,
  • Wet soil


  • Occasional drought,
  • Wet sites,
  • Occasional flooding,
  • Alkaline soil,
  • Clay soil,
  • Road salt

Seasons of Interest:

  • early spring,
  • mid spring,
  • late spring,
  • early summer

Flower Color & Fragrance:

  • Blue,
  • Purple

Shape or Form:

  • Multi-stemmed,
  • Open,
  • Oval,
  • Round,
  • Thicket-forming,
  • Upright

Growth Rate:

  • Fast

More Information:

Tree & Plant Care

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

Disease, pests, and problems

Rust, powdery mildew, stem cankers.

Native geographic location and habitat

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

Attracts birds, pollinators, or wildlife

Birds and butterflies are attracted to flowers.

Bark color and texture 

Gray to brown, slender and twiggy.

Leaf or needle arrangement, size, shape, and texture

Alternate. A large 1-foot long, compound leaf with oblong to oval shaped leaflets.

Flower arrangement, shape, and size

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

Fruit, cone, nut, and seed descriptions

Small, warty, kidney-shaped pod is persistent into winter. 


Location of Amorpha fruticosa (Indigo-bush) at the Arboretum