Preen for your Garden Beds (Stops weeds all season long) Use Preen before you see weeds growing in flower beds. Preen stops weed seeds from germinating. It can be used around established plants & transplants.For best results use every 6 weeks until weeds are under control. On Long Island we recommend to start using Preen (April 1st the same time you use your crabgrass preventer on your lawn). Preen can be used around trees, shrubs, flowers, roses, bulbs & vegetables.
To give your plants fertilizer while weed preventing use Preen & Green. (Keep in mind this is a general fertilizer so you should still fertilize regularly). Use Round up to kill existing weeds or perennial weeds (weeds that already have a root system). Round up is a contact killer and is non selective so it will kill everything it hits .Seeds of killed plants can start to germinate again after 7-10 days , so after you use Round up follow with a Preen. Application.