Amorpha/ false indigo
Amorpha fruticosa, false indigo © Dr. Les Mehrhoff
Amorpha fruticosa, false indigo © Dr. Les Mehrhoff
Amorpha fruticosa, false indigo © Sam Droege, hosted by Discover Life
Amorpha fruticosa, false indigo © Dr. Les Mehrhoff
Genus: Amorpha
Common Name: False Indigo
details
The two most common species of Amorpha, false indigo bush (Amorpha fruticosa) and leadplant (Amorpha canescens) both produce terminal spikes of purple to deep violet flowers, with prominent yellow/orange stamens. These showy blooms, which can enhance a variety of gardens, provide an excellent source of pollen and nectar source for many species of native bees.
Native Regions
Throughout the United States (except Nevada), and eastern Canada
Availability
Several species are routinely available. The smaller species, leadplant (Amorpha canescens), requires sandy or rocky well-drained soil, but is both drought and shade tolerant. The larger shrub, false indigo bush (Amorpha fruticosa), can grow in a variety of soil types and wet to dry conditions, but can become invasive in wetter environments.
Duration
Perennial
Bloom Time
Spring, summer
Average Height
3 to 6 feet, depending upon species
Flower Color
Purple
Exposure
Full sun to partial shade
Water Requirements
Low to average
Recommended Species
Amorpha fruticosa (false indigo, desert false indigo) is distributed throughout the United States, except for Nevada and Montana, and is also native to eastern Canada. It can tolerate moist soils to dry sands and is found growing in a variety of terrains, including stream banks, roadsides, canyons and open woods. This shrub, which often forms thickets on riverbanks and islands, can be weedy or invasive in the northeast. False indigo bush produces 6 inch terminal spikes of deep violet flowers with prominent orange/yellow stamens, from April to June. It attracts a spectrum of native bees and is a larval host for a number of moths and butterflies, including some species of skipper, dogface and hairstreak butterflies. Typically reaching 6 feet in height, this perennial shrub can grow to 10 feet. It works well in ornamental landscaping and is commercially available.
Amorpha canescens (leadplant) is a small, deciduous, perennial shrub, 1-3 feet tall, which produces colorful, purple flower spikes in mid-summer. In the United States, it occurs from Montana east to Michigan and south to New Mexico and Louisiana. In Canada, it is native to areas in Manitoba and Ontario. Leadplant grows in well-drained rocky or sandy soil, occurring naturally in prairies, rocky bluffs and open woodlands. This is one of the most conspicuous and characteristic shrubs of the upland prairies. Leadplant is a floral resource for pollinating insects, in particular providing an excellent source of both pollen and nectar for a variety of native bee species. It is also an ideal ornamental plant for use in gardens, as it has showy flowers, maintains a modest size and is both drought and shade tolerant. It also forms nodules on its roots to fix nitrogen, enhancing soil fertility for itself and surrounding plants. Leadplant is routinely available through native plant and other nurseries in regions where this plant occurs.