Smith Seed Services announces limited availability of WinterKing hairy vetch variety. Selection work on WinterKing originated in Eastern Pennsylvania with selection work by cover crop innovator Steve Groff. WinterKing’s key features are delayed flowering, improved winter hardiness, and the ability to product abundant biomass. This protein/nitrogen-rich biomass is beneficial for grazing, harvested forage, cover cropping, as well as attracting and feeding wildlife and pollinators.

Delayed Flowering

As an annual legume, hairy vetch may need to be terminated either mechanically or chemically when followed by a row crop. Some producers may find the late maturity of WinterKing reduces the potential for undesired seed propagation found in earlier maturing cover crop varieties. For livestock producers, WinterKing’s late maturity means more vegetative high-value feed longer into the spring season


WinterKing has shown potential to produce 150-200#N/acre, especially when allowed to reach maturity later in the season. This is beneficial for green manure as well as providing an extended high-protein source for grazing livestock throughout the full spring season

Improved Winter Hardiness

Better winter hardiness equates to more biomass. More biomass provides increased forage for livestock, more biomass for cover croppers, and increased weed suppression for all. Those desiring high nitrogen-fixing legumes for green manure, forage grazing, wildlife and pollinator attractants should find WinterKing an improved option over other legumes that lack cold tolerance.

Supply is limited. To learn more and find a local dealer, visit or call Smith Seed Services at 888-550-2930.