aren't just for lawns; they may be applied to bedding areas too! The trick is
to make sure that the pre-emergence you select has been approved to be used
alongside the existing plants you want to keep. So, read the label carefully
before buying an herbicide. Pre-emergence are best utilized in established
shrub and/or perennial beds where no digging will be done this spring. When the
soil is disturbed the herbicide is released into the atmosphere and will no
longer prevent weed germination.
Before applying a pre-emergence herbicide remove all existing weeds from the area. Odds are there will be a few there. Either pull them by hand or spray them with a post-emergence herbicide like Round-Up. Just be careful and avoid spraying your desirable plants! Once the area is just how you want it apply the pre-emergence according to label directions. These herbicides are usually applied in a granular form and are scratched into the top layer of soil beneath existing shrubs, perennials, and even some annuals. Treflan and Preen are common pre-emergence herbicides. The granules must be watered in thoroughly to be effective.
After every step has been taken according to label directions, apply a 2" layer of mulch as an added weed barrier. Note: Do not place the mulch directly around the crown or stem of plants. This can cause fungal problems. Leave a 1-2" space around the base, mulching over the root system of the plant. Organic mulch is one of the most beneficial additions to the landscape because it is helpful in many arenas. It maintains a stable soil temperature, improves moisture retention by reducing evaporation and runoff, adds nutrients to the soil as it gradually breaks down, and it prevents weeds.
A few words on weeds:
They know, they just know where to grow, how to dupe you, and how to camouflage themselves among the perfectly respectable plants, they just know, and therefore, I've concluded weeds must have brains. ~Dianne Benson, Dirt, 1994
Crabgrass can grow on bowling balls in airless rooms, and there is no known way to kill it that does not involve nuclear weapons. ~Dave Barry
Go often to the house of friends, for weeds choke the unused path. ~Unknown