Crown vetch or axseed (Coronilla varia)

Berries and leaves of Amur cork tree

 
 

Crown vetch (also known as axseed and purple crown-vetch) is a perennial plant in the pea family. It has been widely planted along roadsides for erosion control and can spread into prairies, forest edges, and riverbanks.

Description

Appearance

Crown vetch is a perennial herbaceous plan. Its stems trail over other plants and can grow 2-6 feet long. Crown vetch plants are brown in winter and early spring and can be visible as brown patches on the landscape.

Leaves and Stem

Crown vetch has compound leaves that have 15-25 leaflets with pairs of leaflets along the leaf stalk and one leaflet at the top. Leaflets have smooth edges. Stems have ridges.

Flowers

Crown vetch has tubular pink flowers characteristic of plants in the pea family. Flowers are grouped in flat-topped clusters. Flower color can vary from white to pink to lavender. Flowers bloom from May through August.

Seeds

Slender seeds are contained in thin, finger-like pods. Seeds can remain viable in the soil for 15 years.

Roots and Rhizomes

Crown vetch can spread vegetatively by horizontal stems growing below the soil surface (rhizomes) that form roots and produce new plants. Rhizomes can grow up to 10 feet long, contributing to extensive vegetative spread.

Biology

Crown vetch is a perennial plant. It can reproduce by seed and also spread vegetatively by underground stems called rhizomes. Plants prefer open and sunny areas. Crown vetch can grow in prairies, grasslands, woodland edges, agricultural areas, roadsides, and along waterways

Origin and Spread

Crown vetch is native to Europe and southeast Asia. It was introduced to the United States during the 1950s as a groundcover, a bank and slope stabilizer along roads and waterways, and as a green fertilizer crop. Crown vetch is widely distributed in Minnesota.

Refer to EDDMapS Distribution Maps for current distribution.

Don't be fooled by these look-alikes

  • Cow vetch, Vicia cracca (invasive) and hairy vetch, Vicia villosa (invasive) – flowers are arranged in a line along the stalk, not clustered at the top as in crown vetch. Crown vetch has a leaflet at the tip of its leaves and does not have tendrils at the tip of its leaves as cow and hairy vetch do.
  • American vetch, Vicia americana (native) – American vetch has a "stipule" where the leaf stalk meets the stem. The stipule on American vetch looks like a small leaf with three points on each side.

There are a variety of vetches, peas, and other legumes in Minnesota that have pea shaped flowers and seed pods.

 
Regulatory Classification

Crown vetch is a Minnesota Department of Agriculture Restricted Noxious Weed meaning it is illegal to import, sell, or transport.

Threat to Minnesota
  • Crown vetch can cover other plants, spread vegetatively, and cover acres of land. Outcompeting other plants reduces species diversity and habitat.
  • Crown vetch is challenging to manage. Its impacts have been particularly an issue in prairies and dunes.
  • As a legume, crown vetch can change nitrogen levels in soils, which can make it difficult for native plants to compete.
  • While crown vetch was planted to control erosion, it may not stabilize slopes as intended.
  • Crown vetch contains chemicals that make it non-palatable to grazing animals. There are conflicting reports on toxicity to grazing animals, so consult with University of Minnesota Extension for grazing guidance.
What you should do

One way that invasive plant seeds and fragments can spread is in soil. Sometimes plants are planted purposefully. You can prevent the spread of invasive plants.

PlayCleanGo: Stop Invasive Species in Your Tracks

  • REMOVE plants, animals & mud from boots, gear, pets & vehicle.
  • CLEAN your gear before entering & leaving the recreation site.
  • STAY on designated roads & trails.
  • PLANT non-invasive species.
Native Substitutes
 
Control Methods

Mechanical control can be done by pulling the plant by hand or with equipment such as a shovel. Plants can resprout from root fragments, so try to remove as much of the plant as possible. Additional control methods may be necessary. Follow Minnesota Department of Agriculture noxious weed disposal guidance. Mowing several times a year can reduce the population, but will likely not eliminate it. Mow repeatedly from May to October to prevent flowering. Do not mow if the plants have produced seeds as mowing will spread the seeds. In areas with native grasses, prescribed burning in late spring for several successive years can encourage the native grasses and increase their ability to compete with crown vetch. Crown vetch can resprout after burns so continue to monitor the population.

Herbicide control can be done using systemic herbicides which are taken up by plants and move within the plant, which can kill leaves, stems, and roots. Spot spray with aminopyralid before the plant begins to flower. Spot spray with clopyralid from May to October while the plant is actively growing. Spot spraying during the growing season with herbicides containing 2,4-D, glyphosate, or triclopyr can also be effective.

Reporting

Report new occurrences by submitting a report through EDDMapS Midwest, emailing Arrest The Pest, calling Arrest the Pest (1-888-545-6684), or contacting your local county agricultural inspector.

Resources