Cow vetch pops up in gardens, but is it a friend or foe?

Cow vetch. Vicia cracca or tufted and bird, blue or boreal vetch, is a species of vetch native to europe and asia.

Vicia cracca (tufted, cow, bird, blue or boreal vetch), is species of vetch native to Europe and Asia. It occurs on other continents as an introduced species, including North America, where it is weed