If you do nothing to eradicate the old plants and seeds this fall, new plants will joyfully pop up come spring. To reduce weed invasion, apply some controls over the winter. Once weeds flower, they're well on their way to producing and distributing seeds. In the case of annuals, you can use a mechanical weeder or digging tool to unearth the plant and possibly even bag it before disposing of it, ensuring that seeds are not scattered. Unless you want weeds in your compost, it's best not to discard invasive plants in your compost pile, recommends Colorado extension agent Robert Cox.
Most herbicides are safe if used according to label directions.
Keep in mind that different climates and soil can limit or encourage certain weeds' spread, which means levels of invasiveness largely depend on where you live. Check with your county extension office for more information on controlling difficult weeds in your area. 15200 W. 6th Ave.