It is much easier if any problem species which might occur are attacked from the beginng of your planting instead of waiting until they increase over time. Walk over your site regularly, cutting, pulling or carefully spot spraying with a squirt of Roundup to eliminate these weeds early on. Watch specifically for Canada Thistle, Birds Foot Trefoil, Leafy Spurge, and Sweet Clover. Most annual broadleaf weeds are not a problem as mowing will control them and they will soon be crowded out by the prairie plants.

If problem cool season grasses such as Quack, Brome or Kentucky Bluegrass begin to invade your site, they can be controlled in one of two ways. A late burn in your prairie, after these grasses are several inches tall, will stunt them and allow the prairie to outcompete them. Cool season grasses can also be controlled with a grass herbicide such as Poast. These hericides should be applied when the weedy cool season grasses are three or four inches tall. This will be before your prairie grasses have emerged so they will not be affected. Poast is available at farm chemical stores. Flowers are not affected in any way by Poast.