This fall’s mild weather is giving gardeners a little extra time to wrap up the year’s chores, including taking care of unwanted plants such as bindweed, poison ivy, wild carrot, dandelion and others. Fall is truly the best time to control perennial and biennial weeds because it is the time when these plants are growing roots and moving sugars into themselves to store up for winter. Fall weed control also gives gardeners a jump-start on spring chores, when many weeds are eager to produce flowers and seeds to ensure their perpetuation.

What makes a weed a weed is another question. Bindweed, Canada and musk thistle, and a few others are designated as noxious weeds by statute and must be controlled by landowners. Poison ivy is not on any official list, but most people consider it a weed and believe control is warranted. Others, such as dandelion, wild mustard, ground ivy (creeping Charlie), and plantain have fans and foes.

Once you decide which plants in your yard and garden are weeds to you, you can work to get rid of them.

The first and most important method for weed control is to follow good cultural practices, and fall is a good time to make sure those are in place.

For flower and landscape beds, use a 3- to 4-inch layer of mulch, plant a spreading groundcover type plant, or otherwise increase the density of desirable plants to keep weeds from filling in bare areas. Weed seeds need light to germinate, so covering them up will keep them from germinating. Get rid of existing weeds first, then add the mulch and/or additional plants. (Fall is also a good time for planting.)

For vegetable and fruit gardens, mulch is also important to keep light from reaching weed seeds. However, if crops are done for the year, the garden can simply be cultivated with a light mulch added over the top. Chopped up leaves (readily available right now), straw, prairie hay, and other materials that break down easily are ideal for vegetable gardens. For perennial crops such as berries, or late crops such as spinach and carrots, remove weeds manually and mulch around them like landscape plants.

For lawns, increasing plant density is the best defense against weeds. While it is a little past the ideal time for fall seeding, early November is one of the recommended times to fertilize cool-season lawns such as fescue and bluegrass. Use a fertilizer with a quick-release nitrogen source to allow the grasses to make the most of it and strengthen their root systems for next year. Then consider dormant seeding later in the winter to increase the density of the stand and fill in bare spots.

Mechanical or physical removal of weeds goes alongside with following good cultural practices. Very few weeds will grow in a fully planted or well-mulched landscape, garden or lawn, so manual removal of the few that appear is a small chore. Use a gardening knife (Hori Hori) or dandelion digger to get the roots out with the rest of the plant.

Herbicides should be used as a last resort for weed management, but they may be especially useful for weeds like poison ivy or weeds that are very hard to kill like field bindweed. Systemic herbicides applied in the fall are transported into plant roots along with sugars that plants are storing and are thus more effective than when applied in the spring. Fall herbicide applications are most effective before the first hard freeze.

— Jennifer Smith is a former horticulture extension agent for K-State Research and Extension and horticulturist for Lawrence Parks and Recreation. She is the host of “The Garden Show.”