Common Name: Bristly Locust

General Information

Robinia hispida is a deciduous shrub with an open, straggly pattern of growth; it usually grows 2 - 3.5 metres tall, though on critical sites is usually smaller. The plant suckers freely from the roots and can spread widely to form thickets, especially on lighter soils[].
The plant is sometimes harvested from the wild for local use as a medicine. It is often grown in soil stabilization and reclamation projects and is sometimes grown as an ornamental, valued especially for its floral display[].
Robinia hispida has a wide distribution range, it is known to occur within the protected area network and there are no major threats to the species at present. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2012)[].
Robinia hispida, especially the form fertilis, has been widely planted in the USA in soil stabilization projects. It spreads freely by suckers and has often become naturalized[].

Known Hazards

None known

Botanical References

,

Range

Southeast N. America - Kentucky to Virginia, south to Alabama and Georgia. Some records show most States in the USA, but probably naturalized there

Habitat

Dry woodland and hillside scrub.

Properties

Weed Potential	Yes
Conservation Status	Least Concern
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	2.00 m
Growth Rate	Medium
Pollinators	Insects
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Robinia hispida is very cold tolerant. When fully dormant, top growth can withstand winter temperatures down to around -25°c without damage - the plant is able to survive temperatures down to around -35°c, though top growth is usually killed bak, though the plant will usually resprout from the base[].
Prefers a position in full sun[], but can tolerate light shade. Succeeds in any soil, preferring one that is not too rich[, ]. Prefers a well-drained soil, succeeding on dry barren sites[, , ]. Plants are tolerant of drought and atmospheric pollution[]. Thrives best at a pH of 6 - 7, but this species is useful for vegetating acid soils with a pH as low as 3.5 to 4.0, as well as alkaline soils with a pH 8.0[].
The branches are brittle and very liable to wind damage and so the plant is best grown with some shelter from stronger winds[, ]. When plants are grown in rich soils they produce coarse and rank growth which is even more liable to wind damage[, ].
Plants can sucker freely, especially when growing on soils of lighter texture. Suckering is severely restricted if there is a dense growth of herbaceous plants[]. Root suckers may appear the first year of growth, and the thicket forming growth habit will begin by the second year[].
When grown as an ornamental, plants are often grafted onto the roots of Robinia pseudoacacia since this reduces the tendancy to sucker[].
Any pruning should be done in late summer in order to reduce the risk of bleeding[].
Plants in this genus are notably resistant to honey fungus[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

None known

Medicinal

The root bark is chewed as an emetic[].
The root is beaten and then held on the tooth to relieve toothache[].

Agroforestry Uses:

This species is one of the best erosion control shrubs for steep sloping sites with active erosion. It fixes atmospheric nitrogen and provides quick, woody, vegetative cover on droughty, critical areas needing stabilizing cover. Although its value for wildlife food is minimal, it only casts a light shade and so does not inhibit the growth of smaller food and cover plants beneath it. It is especially adapted to stabilizing soils with active rill and gully erosion - rill erosion that exposes the roots stimulates root suckering there by creating a denser growth[].
The plant is primarily used for surface mine spoil reclamation, industrial waste piles, roadbanks, cuts and fills, etc[].
It is used as a living fence along major highways in parts of the USA, where its stems trap snow, reducing snow drif on the road and thus improving public safety[].
The plant can make an interesting, informal hedge, though care should be taken with its suckering habit[].
The flowers are a rich source of nectar for bees.

Other Uses

The wood has been used to make fence posts and various small items[].

Propagation

Seed - pre-soak for 48 hours in warm water and sow the seed in late winter in a cold frame[]. A short stratification improves germination rates and time[]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in the following summer. The seed remains viable for over 10 years in normal storage[].
Suckers taken during the dormant season.