Preen Garden Weed Preventer Plus Fertilizer effectively combines the two steps of weed prevention and fertilizing into one easy step. Preen Garden Weed Preventer Plus Fertilizer prevents summer and winter annual weeds from growing in flower and vegetable beds and around trees and shrubs for up to three months. The balanced 9-17-9 fertilizer of nitrogen, phosphorous and potash works to provide abundant blooms, increased yields, strong root development and improved plant vigor. For lawn weed control, see the products listed under Lawns.