Plant Guide

Amorpha fruticosa L.
desert false indigo
AMFR

Summary
Duration	Perennial
Growth Habit	Shrub
U.S. Nativity	Native to U.S.
Federal T/E Status
National Wetland Indicator	FAC, OBL

Morphology/Physiology
Active Growth Period	Spring and Summer
After Harvest Regrowth Rate
Bloat	None
C:N Ratio	High
Coppice Potential	Yes
Fall Conspicuous	No
Fire Resistant	No
Flower Color	White
Flower Conspicuous	No
Foliage Color	Green
Foliage Porosity Summer	Dense
Foliage Porosity Winter	Porous
Foliage Texture	Coarse
Fruit/Seed Color	Brown
Fruit/Seed Conspicuous	Yes
Growth Form	Multiple Stem
Growth Rate	Slow
Height at 20 Years, Maximum (feet)	6
Height, Mature (feet)	18
Known Allelopath	No
Leaf Retention	No
Lifespan	Moderate
Low Growing Grass	No
Nitrogen Fixation	Medium
Resprout Ability	No
Shape and Orientation	Climbing
Toxicity	Slight

Growth Requirements
Adapted to Coarse Textured Soils	Yes
Adapted to Fine Textured Soils	No
Adapted to Medium Textured Soils	Yes
Anaerobic Tolerance	None
CaCO3 Tolerance	Medium
Cold Stratification Required	Yes
Drought Tolerance	Medium
Fertility Requirement	Low
Fire Tolerance	Low
Frost Free Days, Minimum	100
Hedge Tolerance	Low
Moisture Use	Low
pH, Minimum	5.5
pH, Maximum	7.5
Planting Density per Acre, Minimum	700
Planting Density per Acre, Maximum	2700
Precipitation, Minimum	18
Precipitation, Maximum	65
Root Depth, Minimum (inches)	24
Salinity Tolerance	Low
Shade Tolerance	Intolerant
Temperature, Minimum (°F)	-38

Reproduction
Bloom Period	Late Spring
Commercial Availability	Routinely Available
Fruit/Seed Abundance	High
Fruit/Seed Period Begin	Summer
Fruit/Seed Period End	Fall
Fruit/Seed Persistence	No
Propagated by Bare Root	Yes
Propagated by Bulb	No
Propagated by Container	Yes
Propagated by Corm	No
Propagated by Cuttings	No
Propagated by Seed	Yes
Propagated by Sod	No
Propagated by Sprigs	No
Propagated by Tubers	No
Seed per Pound	77000
Seed Spread Rate	Rapid
Seedling Vigor	Medium
Small Grain	No
Vegetative Spread Rate	None

Suitability/Use
Berry/Nut/Seed Product	No
Christmas Tree Product	No
Fodder Product	No
Fuelwood Product	None
Lumber Product	No
Naval Store Product	No
Nursery Stock Product	No
Palatable Browse Animal	Low
Palatable Graze Animal	Low
Palatable Human	No
Post Product	No
Protein Potential	Medium
Pulpwood Product	No
Veneer Product	No

Amorpha fruticosa L.
desert false indigo
AMFR
Cultivar: Dark Lance

Summary
Duration	Perennial
Growth Habit	Shrub
U.S. Nativity	Native to U.S.
Federal T/E Status
National Wetland Indicator	FAC, OBL

Morphology/Physiology
Active Growth Period	Summer
After Harvest Regrowth Rate
Bloat
C:N Ratio	High
Coppice Potential	Yes
Fall Conspicuous	Yes
Fire Resistant	No
Flower Color	Purple
Flower Conspicuous	Yes
Foliage Color	Yellow-Green
Foliage Porosity Summer	Dense
Foliage Porosity Winter	Porous
Foliage Texture	Fine
Fruit/Seed Color	Brown
Fruit/Seed Conspicuous	No
Growth Form	Multiple Stem
Growth Rate	Moderate
Height at 20 Years, Maximum (feet)	6
Height, Mature (feet)	18
Known Allelopath	No
Leaf Retention	No
Lifespan	Moderate
Low Growing Grass	No
Nitrogen Fixation	Medium
Resprout Ability	Yes
Shape and Orientation	Rounded
Toxicity	None

Growth Requirements
Adapted to Coarse Textured Soils	Yes
Adapted to Fine Textured Soils	Yes
Adapted to Medium Textured Soils	Yes
Anaerobic Tolerance	Medium
CaCO3 Tolerance	Low
Cold Stratification Required	Yes
Drought Tolerance	None
Fertility Requirement	Low
Fire Tolerance	None
Frost Free Days, Minimum	100
Hedge Tolerance	Medium
Moisture Use	High
pH, Minimum	5
pH, Maximum	8.5
Planting Density per Acre, Minimum	1200
Planting Density per Acre, Maximum	2700
Precipitation, Minimum	10
Precipitation, Maximum	45
Root Depth, Minimum (inches)	12
Salinity Tolerance	Medium
Shade Tolerance	Intolerant
Temperature, Minimum (°F)	-38

Reproduction
Bloom Period	Early Spring
Commercial Availability	Routinely Available
Fruit/Seed Abundance	High
Fruit/Seed Period Begin	Summer
Fruit/Seed Period End	Fall
Fruit/Seed Persistence	No
Propagated by Bare Root	Yes
Propagated by Bulb	No
Propagated by Container	Yes
Propagated by Corm	No
Propagated by Cuttings	Yes
Propagated by Seed	Yes
Propagated by Sod	No
Propagated by Sprigs	No
Propagated by Tubers	No
Seed per Pound	52000
Seed Spread Rate	Moderate
Seedling Vigor	Medium
Small Grain	No
Vegetative Spread Rate	None

Suitability/Use
Berry/Nut/Seed Product	No
Christmas Tree Product	No
Fodder Product	No
Fuelwood Product	None
Lumber Product	No
Naval Store Product	No
Nursery Stock Product	Yes
Palatable Browse Animal	Low
Palatable Graze Animal	Low
Palatable Human	No
Post Product	No
Protein Potential	Low
Pulpwood Product	No
Veneer Product	No

Kingdom Plantae -- Plants

Subkingdom Tracheobionta -- Vascular plants

Superdivision Spermatophyta -- Seed plants

Division Magnoliophyta -- Flowering plants

Class Magnoliopsida -- Dicotyledons

Subclass Rosidae

Order Fabales

Family Fabaceae -- Pea family

Genus Amorpha L. -- false indigo P

Species Amorpha fruticosa L. -- desert false indigo P

Alternate Names

River-locust, false indigo, indigobush amorpha, indigobush

Uses

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).

Status

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.

Description

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.

Adaptation

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.

Establishment

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.

Management

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).

Cultivars, Improved and Selected Materials (and area of origin)

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

References

Abrams, L. 1944. Illustrated flora of the Pacific States. Vol II. Stanford University Press, Stanford, California.

Dirr, M.A. 1997. Dirr’s hardy trees and shrubs: an illustrated encyclopedia. Timber Press, Portland, Oregon.

Freeman, C.C. & E.K. Schofield 1991. Roadside wildflowers of the Southern Great Plains. University Press of Kansas, Lawrence, Kansas.

Genders, R. 1994. Scented flora of the world. Robert Hale, London.

Hylander, C.J. 1954. The MacMillan wildlower book. The MacMillan Company, New York, New York.

Huxley, A.1992. The new RHS dictionary of gardening. MacMillian Press, New York, New York.

McMinn, H.E. 1939. An illustarted manual of California shrubs. University of California Press, Berkeley, California.

Sheat, W.G. 1948. Propagation of trees, shrubs and conifers. MacMillan & Company.

Steyermark, J.A. 1963. Flora of Missouri. The Iowa State University Press, Ames, Iowa.

The Great Plains Flora Association 1986. Flora of the Great Plains. University Press of Kansas, Lawrence, Kansas.

Prepared By

Lincoln M. Moore

USDA, NRCS, National Plant Data Center

Baton Rouge, Louisiana

Species Coordinator

Lincoln M. Moore

USDA, NRCS, National Plant Data Center

Baton Rouge, Louisiana

Edited: 05apr02 ahv; 25feb03 ahv 30may06jsp

For more information about this and other plants, please contact your local NRCS field office or Conservation District, and visit the PLANTS Web site<https://plants.usda.gov> or the Plant Materials Program Web site <https://Plant-Materials.nrcs.usda.gov>

Attribution: U.S. Department of Agriculture