Formulation: Poast Absorbed by Foilage and Travels Through Entire Plant Will Slow or Stop Growth Within 2 Days. Controls Annual and Perennial Grass Weeds. Systemic selective broad spectrum post-emergent herbicide that can be sprayed over desired plants listed to control annual and perennial grasses. Can be used on vegetables, gardens, trees, shrubs, ornamentals and ground covers. Stops growth of weed grasses within 2 days. Works better with Hi-Yield® Spreader Sticker. Read more about Hi-Yield® Spreader Sticker .