Cow vetch (also known as bird vetch) and hairy vetch are legumes which have been planted in Minnesota for forage and have escaped and established in roadsides and disturbed sunny areas.
Cow vetch and hairy vetch are annual or short-lived perennial herbaceous plants in the legume (pea) family. Their weak stems grow 2 – 3 feet high and grow over other plants, smothering them. The stem of hairy vetch has spreading hairs.
Leaves and Stem
Leaves are alternate (come off the stem one at time at each leaf node) and are composed of leaflets along both sides of a common stalk (pinnately compound). Each leaf has 8 -12 pairs of narrow, oval-shaped, opposite leaflets. The tip of the leaf has a thin tendril that can wrap around other plants or objects. Hairy vetch has hairy stems and leaves while cow vetch has few hairs.
Cow vetch has violet-blue flowers and hairy vetch has flowers that can be violet-blue or can have some white. For both species, the flowers are clustered on one-sided spikes and bloom from May to August.
Seed pods and seeds
Cow vetch and hairy vetch are part of the legume family and produce seed pods that look like pea or bean seed pods. Seed pods are green while maturing and once mature the seed pods of cow vetch are brownish, lance-shaped, and flat while pods of hairy vetch are gray/black to brown and hairy. These numerous, inch-long seed pods contain the seeds themselves.
Both species have taproots that are 1-3 feet long.
Both species are annual or short-lived perennial plants that reproduce by seeds. They grow best on the dry sandy soils of disturbed fields and thickets.
Origin and Spread
Cow vetch and hairy vetch are native to Europe and Asia. They have been widely planted in North America as cover crops and as forage species for cattle. Both species are widely distributed in Minnesota.
Don't be fooled by these look-alikes
- Crown vetch, Securigera varia (invasive) – crown vetch flowers are clustered at the top of stalks as opposed to the flowers arranged along the stalk on cow and hairy 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
Cow vetch and hairy vetch are not regulated.
- Threat to Minnesota
Cow vetch and hairy vetch are not thought to be a threat to healthy native prairies at this time, but can be a problem in prairie reconstructions and on disturbed sites.
- 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.
- REMOVE plants, animals & mud from boots, gear, pets & vehicles.
- 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 up plants before seeds develop.
Herbicide control can be done using systemic herbicides such as clopyralid. Systemic herbicides are taken up by plants and move within the plant, which can kill leaves, stems, and roots.
Management recommendations for crown vetch in the Minnesota Department of Transportation Noxious Weed booklet may also be effective to control cow vetch and hairy vetch.
These species are unregulated, but you can add to the public information about this species by reporting new occurrences through EDDMapS Midwest.