Bristly locust or Rose Acacia

Perennial shrub in the pea family with rose-colored flowers and red bristly stalks.

Other names for this plant include:

• Scientific names: R. hispida var. fertilis, R. hispida var. hispida, R. grandiflora

Classification in Wisconsin: Restricted

Ecological Threat

• Invades numerous habitat types: upland forests, forest edges, prairies, forested dunes, grasslands, roadsides, and disturbed vacant areas.
• Previously planted as fence rows, escaping cultivation.
• Tolerant of many soils but most readily colonizes light-textured soils with good drainage, preferring sandy and silt loams.
• Nitrogen-fixing microbial symbionts alter soil chemistry.
• Expands create dense thickets.
• Seeds remain viable in the soil for 1-10 years.
• Multiple sterile and nonsterile varieties exist, with both types naturalizing.

Identification

Leaves & stems: Alternate, pinnately compound leaves. Small round leaflets are bright green and paler on the underside. Stems covered in thick red bristles. The bark is grey-brown and covered in raised lenticels.

Flowers, fruits & seeds: Rose-colored pea flowers. Seed pods are brown and flat, covered in dense reddish bristles.

Roots: Spreads by root suckering.

Control

Mechanical:

• Pull small plants, and use a weed wrench on larger shrubs.
• Remove all roots if possible, and monitor for resprouts.

Chemical:

• Use cut stump or basal bark herbicide techniques with glyphosate or triclopyr in the fall.
• Monitor for resprouts.

Resources

Sources for content:

• University of Wisconsin - Stevens Point; Robert W. Freckmann Herbarium.
• Virginia Tech Department of Forest Resources and Environmental Conservation.

Links for more information:

• Wisconsin State Herbarium