Abstract: A wing assembly is mountable to a plow blade driven in a direction of travel by a vehicle, and preferably left and right wing assemblies are respectively mounted on the left and right side edges of the plow blade. A representative wing assembly provides an auxillary plowing surface and has an inboard edge that is proximate the plow blade when the wing plate is mounted thereon. The wing plate is pivotally mounted on a vertical pivot axis so that it may pivot into an attack position at an obtuse angle .theta. to the plow blade with the inboard wing edge proximate the plow blade and an outboard portion projecting forwardly and outwardly from the front plowing surface of the plow blade. A latching structure retains the wing plate in the attack position. The pivotal mounts may be vertically aligned trunnion pins on the plow blade and matable opening on brackets defined by rear horizontal support and mounting webs on the wing plate. Where the plow blade can be canted at an obtuse angle .phi.