False Indigo looks like a Leadplant (Amorpha canescens) on steroids. It is taller than the latter shrub and its leaflets are larger in size. In southern Illinois and other southern regions, there is some variability in the size, shape, and hairiness of the leaflets. As a result, different varieties of False Indigo have been described, but most of them are rare in Illinois; only the typical variety is occasional throughout the state. Another shrub with a similar appearance, Amorpha nitens (Shiny False Indigo), has shiny leaflets that are hairless (or nearly so). This rare shrub can be found in southern Illinois, but it is absent from the rest of the state. Other common names of Amorpha fruticosa are Indigo Bush and River Locust.

This is a native shrub about 4-16' tall that branches occasionally. The lower stems are woody; the gray bark is relatively smooth with scattered small lenticels. The upper stems are dull light green and pubescent. The alternate leaves are about ½–1½' long and odd-pinnate with 11-35 leaflets; they have relatively short petioles up to 2' long. Both the petioles and central stalks of the leaves are light gray-green and pubescent. Individual leaflets are 1-2' long and ½–1' across; they are dull gray-green, oblong to broadly oblong, smooth along their margins, and sparsely canescent-pubescent. From the leaflet undersides, scattered translucent glands are visible that resemble small dots. Each leaflet has a tiny pointed tip. The petiolules of the leaflets are slender and short. Occasionally, clusters of 1-6 spike-like racemes of flowers develop from the upper branches. Individual racemes are erect to ascending, 3-8' long, and cylindrical in shape from the dense arrangement of flowers. Each flower is ¼' long (or a little more) and tubular in shape from a single violet-purple petal (the standard) that wraps around the reproductive organs; there is a single style and about 10 stamens that are strongly exerted. The anthers of the stamens are bright orange-yellow. The blooming period occurs from late spring to early summer and lasts about 2-3 weeks. The flowers are replaced by small seedpods about ¼' long (or a little more) that each contain 1-2 seeds. The seedpods are obovoid and somewhat flattened, terminating in short beaks; their outer surfaces are glandular-punctate. The root system is woody and branching. Sometimes small colonies of plants develop at favorable sites.

General: Bean family (Fabaceae). Desert false indigo is a native, deciduous shrub growing between three to ten feet high. The leaves are four to eight inches long, with eleven to twenty-five leaflets, ovate to oblong. This species is highly variable as regards to shape of the leaf and pubescence (The Great Plains Flora Association 1986). The scented flowers are purplish blue with orange anthers and occur in three to six inch long upright spikes in June (Dirr 1997). The fruits are short, smooth or hairy, glandular legumes containing a single smooth brownish seed (Freeman & Schofield 1991).

Distribution: Desert false indigo occurs in the foothills of the San Bernardino and San Jacinto mountains southward in the lower mountain valleys of San Diego county in the upper Sonoran Life Zone (McMinn 1939). It extends southward to Lower California and eastward to Texas and the Atlantic Coast. This species is also found from Connecticut to Minnesota, south to Florida and Louisiana (Dirr 1997). For current distribution, please consult the Plant profile page for this species on the PLANTS Web site.

River-locust, false indigo, indigobush amorpha, indigobush

False Indigo is occasional throughout Illinois (see Distribution Map). Habitats include riverbanks, soggy thickets, open bottomland woodlands, edges of marshland, and wet prairies along rivers. It is likely that populations of this shrub have been declining because of habitat destruction.

Amorpha dewinkeleri Small:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha fruticosa var. occidentalis (Abrams) Kearney & Peebles:
Mexico (Mesoamerica)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha fruticosa var. oblongifolia E.J. Palmer:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha fruticosa var. tennesseensis (Shuttlew. ex Kunze) E.J. Palmer:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha fruticosa var. croceolanata (P. W. Watson) Mouill.:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha fruticosa var. angustifolia Pursh:
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha fragrans Sweet:
Mexico (Mesoamerica)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha virgata Small:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha tennesseensis Shuttlew. ex Kunze:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha fruticosa L.:
Argentina (South America)
Canada (North America)
Mexico (Mesoamerica)
United States (North America)
China (Asia)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha curtissii Rydb.:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha croceolanata P. W. Watson:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Amorpha bushii Rydb.:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Distribution: Native of U.S.A., cultivated in Abbottabad, Lahore.  Cultivated as an ornamental plant.

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Amorpha fruticosa is commonly found on wet ground along rivers, streams, ponds, and ditches and occasionally in open wet woods (Freeman & Schofield 1991). It requires well-drained soil and can grow in nutritionally rich soil. This plant prefers acid, neutral or basic soils. It is adaptable to infertile, dry and sandy soils. Once planted, it remains for life (Dirr 1997). Utilize in dry soil and full sun where precious few plants will prosper.

A deciduous shrub, 1.5-6.0 m tall. Leaf 15-30 cm long, leaflets 11-25, 1.2-4.0 cm long, oval or elliptic, obtuse, mucronate, black dotted on the lower surface. Inflorescence a terminal raceme, 7.5-15.0 cm long. Pedicel c. 2 mm long. Calyx c. 2.5 mm long, teeth unequal, the upper shorter. Vexillum dark purple-blue, c. 5 mm long. Fruit 7.5-10.0 mm long, glandular, curved near the tip.

Perennial, Shrubs, Stems woody below, or from woody crown or caudex, Plants with rhizomes or suckers, Nodules present, Stems erect or ascending, Stems less than 1 m tall, Stems 1-2 m tall, Stems greater than 2 m tall, Stems solid, Stems or young twigs sparsely to densely hairy, Stem hairs hispid to villous, Leaves alternate, Leaves petiolate, Stipules inconspicuous, absent, or caducous, Stipules membranous or chartaceous, Stipules setiform, subulate or acicular, Stipules deciduous, Stipules free, Leaves compound, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets alternate or subopposite, Stipels present at base of leaflets, Leaflets 10-many, Leaves glandular punctate or gland-dotted, Leaves glabrous or nearly so, Leaves hairy on one or both surfaces, Inflorescences racemes, Inflorescences spi kes or spike-like, Inflorescence axillary, Bracts very small, absent or caducous, Flowers zygomorphic, Calyx 5-lobed, Calyx glabrous, Calyx hairy, Corolla reduced to 1 petal, Petals separate, Petals clawed, Petals blue, lavander to purple, or violet, Banner petal ovoid or obovate, Stamens 9-10, Stamens monadelphous, united below, Stamens long exserted, Filaments glabrous, Anthers versatile, Style terete, Fruit a legume, Fruit unilocular, Fruit indehiscent, Fruit elongate, straight, Fruit oblong or ellipsoidal, Fruit strongly curved, falcate, bent, or lunate, Fruit exserted from calyx, Fruit glabrous or glabrate, Fruit 1-seeded, Seeds ovoid to rounded in outline, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.

Isolectotype; Isosyntype for Amorpha virgata Small
Catalog Number: US 24294
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined; Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): J. K. Small
Year Collected: 1893
Locality: N.W. Slope of Stone Mountain, De Kalb, Georgia, United States, North America
Elevation (m): 305 to 427

Isolectotype; Isosyntype for Amorpha virgata Small
Catalog Number: US 1364530
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined; Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): J. K. Small
Year Collected: 1893
Locality: NW slope of Stone Mountain., De Kalb, Georgia, United States, North America
Elevation (m): 305 to 427

Isolectotype; Type collection for Amorpha dewinkeleri Small
Catalog Number: US 1738292
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): J. K. Small
Year Collected: 1917
Locality: Near Ft. Schackleford, Big Cypress, Lee, Florida, United States, North America

Isotype for Amorpha curtissii Rydb.
Catalog Number: US 24265
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Verified from the card file of type specimens
Preparation: Pressed specimen
Collector(s): A. H. Curtiss
Year Collected: 1894
Locality: Jacksonville., Duval, Florida, United States, North America

Isotype for Amorpha occidentalis Abrams
Catalog Number: US 613982
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): L. Abrams
Year Collected: 1903
Locality: San Diego River, near old San Diego Mission., San Diego, California, United States, North America

False Indigo is occasional throughout Illinois (see Distribution Map). Habitats include riverbanks, soggy thickets, open bottomland woodlands, edges of marshland, and wet prairies along rivers. It is likely that populations of this shrub have been declining because of habitat destruction.

Propagation by Seed: Amorpha fruticosa seeds should be presoaked for twelve hours in warm water and sown in the early spring in a greenhouse. The seeds normally germinate at 20ºC in one to two months. When the seedlings are large enough to handle place them into individual pots and grow them in the greenhouse for their first winter. Plant them in their permanent position in the late spring or early summer.

The flowers are pollinated primarily by small to medium-sized bees, which seek nectar and pollen. These bee visitors include Halictid bees (Lasioglossum spp.), Masked bees (Hylaeus spp.), Andrenid bees (Andrena spp.), Little Carpenter bees (Ceratina spp.), and Cuckoo bees (Nomada spp., Coelioxys spp.). The Andrenid bee, Andrena quintilis, is a specialist pollinator (oligolege) of Amorpha spp., including False Indigo. The caterpillars of Epargyreus clarus (Silver-Spotted Skipper), the butterfly Colias cesonia (Dogface Sulfur), and the moth Dasylophia anguina (Black-Spotted Prominent) feed on foliage of False Indigo, while the caterpillars of the moth Pleuroprucha insularia (Common Tan Wave) feed on the flowers. Other insects that feed on this shrub include the lace bug Gargaphia amorphae, the plant bugs Psallus amorphae and Lopidea hesperus, and the larvae of the Long-Horned beetle Megacyllene decora (which bore through the stems). There are also several leaf beetles that feed on the leaves (Anomoea flavokansiensis, Anomoea laticlavia, Odontata dorsalis, Phyllecthris dorsalis, and Sumitrosis rosea). White-Tailed Deer browse on this shrub sparingly.

Amorpha fruiticosa (Indigo Bush)
(Also called False Indigo; bees suck nectar or collect pollen, while the beetle sucks nectar or feeds on pollen; observations are from Robertson, Krombein et al., and Mawdsley as indicated below)

Bees (long-tongued)
Anthophoridae (Ceratinini): Ceratina dupla dupla sn cp fq (Rb); Anthophoridae (Nomadini): Nomada articulata sn (Rb); Megachilidae (Coelioxini): Coelioxys sayi sn (Rb)

Bees (short-tongued)
Halictidae (Halictinae): Lasioglossum imitatus sn cp (Rb), Lasioglossum pectoralis sn cp (Rb), Lasioglossum tegularis sn cp (Rb); Halictidae (Nomiinae): Nomia nortoni (Kr); Colletidae (Hylaeinae): Hylaeus affinis sn (Rb), Hylaeus modestus modestus sn (Rb), Hylaeus saniculae sn (Rb); Andrenidae (Andreninae): Andrena ceanothi (Kr), Andrena illinoiensis (Kr), Andrena imitatrix imitatrix (Kr), Andrena quintilis cp olg (Kr), Andrena ziziae (Kr)

Beetles
Cleridae: Phyllobaenus pubescens (Mwd)

In Great Britain and/or Ireland:
Foodplant / feeds on
Diplodia coelomycetous anamorph of Diplodia amorphae feeds on Amorpha fruticosa

Fl.Per.: April.

The following is a representative barcode sequence, the centroid of all available sequences for this species.


No available public DNA sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 4
Specimens with Barcodes: 13
Species With Barcodes: 1

Canada

Rounded National Status Rank: N1 - Critically Imperiled

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Please consult the Plants Web site and your State Department of Natural Resources for this plant’s current status, such as, state noxious status, and wetland indicator values.

These species are introduced in Switzerland.

Materials are available through native plant seed sources within its range.

Desert false indigo has a symbiotic relationship with certain soil bacteria. These bacteria form nodules on the roots and fix atmospheric nitrogen. The growing plant utilizes some of this nitrogen but other plants growing nearby can also use some (Huxley 1992).

The preference is full or partial sun and wet to moist conditions. False Indigo adapts to different kinds of soil, tolerating occasional flooding. With the assistance of symbiotic bacteria, it fixes nitrogen in the ground.

Ethnobotanic: Resinous pustules on the plant contain amorpha, a contact and stomachic insecticide that also acts as an insect repellant (Huxley 1992). Desert false indigo also contains some indigo pigment that can be used to make blue dye.

Landscape: Amorpha fruticosa is an exotic species that is often planted as an ornamental. This shrub has an extensive root system and is also fairly wind tolerant; it can be planted as a windbreak and also to prevent soil erosion (Huxley 1992). According to Dayton, the early settlers used this shrub as a substitute for true indigo (McMinn 1939).