Preen southern weed preventer is formulated specifically for tough southern weeds and warm climates. It inhibits most weeds from germinating for up to 4 months in flower beds, around ground covers, trees and shrubs. Although this product will not kill existing weeds, it will prevent new weeds from sprouting eliminates the need for difficult and time consuming hand weeding. Without weeds, your valuable plants can grow larger and stronger and your beds will stay neat and weed-free all season long.