hairy indigo
(Indigofera hirsuta)
This species is Introduced in the United States
ORIGIN: Africa, southern Asia, Australia
GROWTH TRAITS: Herbaceous annual that can grow erect up to 3.2' (1 m) tall from a deep central taproot. More frequently, however, it forms a spreading, low-growing groundcover. Stems are reddish, rounded, slightly ridged, and covered in reddish hairs. Leaves are alternate, 1-4" (2.5-10 cm) long, and divided into 5-7 opposite leaflets with one terminal leaflet. Leaflets are 0.6-1.6" (1.5-4 cm) long, elliptical-oblong, and have smooth margins. The terminal leaflet is longer than the lateral leaflets. Both sides of leaflets are hairy. Numerous flowers are produced in late summer through fall and are clustered together at the tips of flowering stems. Flowers are pea-like (having a banner, wing and keel, typical of the pea family) and can be brick red to rose-colored. Sepals are covered in stiff, brown hairs. Fruits are straight, skinny, pods up to 0.8" (2 cm) long. They are covered in small hairs and contain 6-9 brown, cubic seeds.
REPRODUCTION: Spreads by seed. Seeds remain viable for at least four years.
HABITAT: Grows best on open, disturbed sites and tolerates sandy, infertile soil as well as dry and moist conditions. It typically invades cultivated and waste areas, grasslands, savanna, dry and deciduous forests, river banks, and beaches. It does not tolerate frost.
LOOK-ALIKES: The combination of groundcover growth, alternate leaves with opposite leaflets, hairy stems, and pea-like flowers help differentiate roughhairy indigo from unrelated look-alikes. Several species of Indigofera occur in the USA and may resemble roughhairy indigo at various stages. Most of these potential look-alikes can be differentiated by growing as taller shrubs, lacking hairs, having pink flowers, and different shapes/sizes to their leaves and fruits. For example, the exotic softhairy indigo (I. pilosa) lacks the red/ brown hairs and dense foliage of roughhairy indigo. The native upright indigo (I. suffruticosa) is a less hairy shrub with thicker, more curved fruits.
CITATIONS:
Rawlins, K.A., R.L. Winston, C.T. Bargeron, D.J. Moorhead, and R. Carroll. 2018. New Invaders of the Southeast. USDA Forest Service, Forest Health Assessment and Applied Sciences Team, Morgantown, West Virginia. FHTET-2017-05. Retrieved from http://bugwoodcloud.org/resource/pdf/FHTET-2017-05_New%20Invaders_SE.pdf
GROWTH TRAITS: Herbaceous annual that can grow erect up to 3.2' (1 m) tall from a deep central taproot. More frequently, however, it forms a spreading, low-growing groundcover. Stems are reddish, rounded, slightly ridged, and covered in reddish hairs. Leaves are alternate, 1-4" (2.5-10 cm) long, and divided into 5-7 opposite leaflets with one terminal leaflet. Leaflets are 0.6-1.6" (1.5-4 cm) long, elliptical-oblong, and have smooth margins. The terminal leaflet is longer than the lateral leaflets. Both sides of leaflets are hairy. Numerous flowers are produced in late summer through fall and are clustered together at the tips of flowering stems. Flowers are pea-like (having a banner, wing and keel, typical of the pea family) and can be brick red to rose-colored. Sepals are covered in stiff, brown hairs. Fruits are straight, skinny, pods up to 0.8" (2 cm) long. They are covered in small hairs and contain 6-9 brown, cubic seeds.
REPRODUCTION: Spreads by seed. Seeds remain viable for at least four years.
HABITAT: Grows best on open, disturbed sites and tolerates sandy, infertile soil as well as dry and moist conditions. It typically invades cultivated and waste areas, grasslands, savanna, dry and deciduous forests, river banks, and beaches. It does not tolerate frost.
LOOK-ALIKES: The combination of groundcover growth, alternate leaves with opposite leaflets, hairy stems, and pea-like flowers help differentiate roughhairy indigo from unrelated look-alikes. Several species of Indigofera occur in the USA and may resemble roughhairy indigo at various stages. Most of these potential look-alikes can be differentiated by growing as taller shrubs, lacking hairs, having pink flowers, and different shapes/sizes to their leaves and fruits. For example, the exotic softhairy indigo (I. pilosa) lacks the red/ brown hairs and dense foliage of roughhairy indigo. The native upright indigo (I. suffruticosa) is a less hairy shrub with thicker, more curved fruits.
CITATIONS:
Rawlins, K.A., R.L. Winston, C.T. Bargeron, D.J. Moorhead, and R. Carroll. 2018. New Invaders of the Southeast. USDA Forest Service, Forest Health Assessment and Applied Sciences Team, Morgantown, West Virginia. FHTET-2017-05. Retrieved from http://bugwoodcloud.org/resource/pdf/FHTET-2017-05_New%20Invaders_SE.pdf
Maps
EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org
Taxonomic Rank
| Domain: Eukarya |
| Kingdom: Plantae |
| Phylum: Magnoliophyta |
| Class: Magnoliopsida |
| Superorder: Rosanae |
| Order: Fabales |
| Family: Fabaceae |
| Subfamily: Faboideae |
| Tribe: Indigofereae |
| Genus: Indigofera |
| Indigofera hirsuta |
Other System Links
Plants: INHI
Bayer: INDHI
GRIN: 20017
ITIS: 26741
NPDN Pest: PCQCBBA
NPDN Host: 31789
References
Common Name Reference: Weed Science Society of America Common Names List
Scientific Name Reference: USDA, NRCS. 2010. The PLANTS Database. National Plant Data Center, Baton Rouge, LA, USA.