Miller, James H.; Manning, Steven T.; Enloe, Stephen F. 2010. A management guide for invasive plants in southern forests. Gen. Tech. Rep. SRS–131. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 120 p.
Crownvetch [Securigera varia (L.) Lassen] (formerly Coronilla varia L.) is a deciduous perennial forb sprawling to form tangled mats to 3 feet (92 cm) high or scrambling over rocks, shrubs, and small trees. Feathery pinnately compound leaves [similar to true vetch species (Vicia spp.) but lacking tendrils], alternate on slender reclining stems. In summer a multitude of showy stemmed heads of white and pink flowers jut above entangled plants that yield tufts of slender seed pods in fall. One plant can cover 15 square feet (1.5 m2) or more in a year from underground stems (rhizomes) with taproots. Forms brown, flattened patches in winter that resprout quickly in spring or remain green in southern areas. Seeds can germinate immediately after release, while viability in the soil seed bank is questioned. Persistent rhizomes sustain most patches and make control difficult. Crownvetch is planted on roadsides, surface mines, and in gardens and escapes into forest edges, openings, streamsides, and special habitats like rock outcroppings. It displaces plants and forms monocultures. Seed spread by wildlife and people while sediment-buried stems and rhizomes become established along streams.
Management strategies
- Do not plant. Remove prior plantings, and control sprouts and seedlings. Bag and dispose of plants, rhizomes, and fruit in a dumpster or burn.
- Treat when new plants are young to prevent seed formation.
- Pull, cut, and treat when seed are not present.
- Repeated mowing can stop seed production.
- Minimize disturbance within miles of where this plant occurs, and anticipate wider occupation when plants are present before disturbance.
- Manually pull when soil is moist to ensure removal of all rhizomes.
- Readily eaten by most livestock, although reportedly toxic to horses.
Recommended control procedures
- Thoroughly wet all leaves with a glyphosate herbicide or Garlon 3A as a 1- to 2-percent solution (4 to 8 ounces per 3-gallon mix) or Milestone VM* as a 0.5-percent solution (2 ounces per 3-gallon mix) in water with a surfactant during the vegetative stage prior to branching or during flowering. Apply Transline* † as a 0.5-percent solution (2 ounces per 3-gallon mix); Arsenal AC* as a 0.5 percent solution (2 ounces per 3-gallon mix); or Arsenal PowerLine* as a 1-percent solution (4 ounces per 3-gallon mix) in fall, before frost or leaf drop.
* Nontarget plants may be killed or injured by root uptake.
† Transline controls a narrow spectrum of plant species.
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