Crownvetch (Securigera varia)

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Rosanae
Order	Fabales
Family	Fabaceae
Genus	Securigera

Scientific Name

Securigera varia

Scientific Name Synonyms

Coronilla varia

Common Name

purple crown-vetch

Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.

Plant

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 seedpods 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, “earth hugging” patches in winter that resprout quickly in spring or remain green in southern areas. Caution: All parts are poisonous to some degree.

Stem

Ascending to sprawling, green, slender and succulent but wiry, slightly angled, 20 to 80 inches (50 to 200 cm) long, with leaves and flower/seed stalks arising along the stem at regular intervals.

Leaves

Alternate, odd-pinnately compound, 2 to 4 inches (5 to 10 cm) long, arising immediately from the stem with 2 tiny stipules. Leaflets 11 to 25, dark green, oblong to obovate, 0.3 to 0.8 inch (0.8 to 2 cm) long with minute hairlike tips.

Flowers

May to September. Small, multicolored pea-type flowers with pink and purple or rose upper petals and white to pinkish-white lower keel petals, 5 to 25 flowers clustered in cloverlike “crowns” about 1 inch (2.5 cm) wide, jutting upward on thin axillary stalks, 2 to 6 inches (5 to 15 cm) long, above entangled plants.

Fruit and seeds

Present May to July and maturing in October. Radiating clusters of slender, pointed seedpods (loments), 2 to 4 inches (5 to 10 cm) long, light green maturing to brown. Segmented to divide and release 3 to 12 flattened brown seeds.

Ecology

Nitrogen fixer and pollinated by insects. Grows in full sun to light shade and the range of conditions common to the South. Tolerates drought, heavy precipitation and cold temperatures. Planted on roadsides, surface mines and in gardens, escaping into forest edges, openings, streamsides and special habitats like rock outcroppings. Displaces plants to form monocultures. Spread by wildlife- and people-dispersed seeds while plant parts buried by sediment along streams can root and grow. Seeds can germinate immediately after release or remain viable in the soil for several years. While reportedly poisonous, especially to horses, it is used for livestock forage. Deer eat crownvetch and it provides cover for rabbits and ground-nesting birds.

Resembles

Resembles the growth habit and leaves of vetches (Vicia spp.) that have tendrils at their leaf ends and scattered flowers, not in clusters like crownvetch.

History and use

Introduced in 1784 from Europe, although originally from Eastern China. Ornamental widely planted in cities due to pollution and drought tolerance.

Distribution

Found in scattered infestations throughout the region.

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.

Images

June	September	Summer	June
June	September

Download the publication