Preen Garden Weed Preventer Plus Plant Food works all season long! Unlike other weed killers and plant foods, one easy application prevents weeds up to 3 months. Feeds your plants for beautiful color, foliage and strong roots to help avoid insects and disease. This product can be used anytime during the spring, summer, or fall in flower and ornamental garden beds, around ground covers, trees, and shrubs. Although this product will not kill existing weeds. It will prevent new weeds from sprouting – eliminating the need for difficult and time-consuming hand weeding. There is no chance of overfeeding or burning your plants when used as directed. Without weeds, your valuable plants can grow larger and stronger. Your beds will stay neat and weed-free all season long!