If you’re tired of weeds, now’s the time to get rid of them. Here’s how to do it

Here’s a familiar phrase in the turf world: Give a weed an inch, and it will take a yard. But armed with a bit of knowledge and the right timing, weeds can be stopped in their tracks. Many people are surprised to learn that now is an excellent time to get ahead of the spring weeds.

Bright yellow dandelions, purple hues of henbit and limey-green chickweed germinate in the fall and winter and appear with the arrival of spring. As a result, this group of weeds is often referred to as winter annuals. Henbit and chickweed are annuals and die off as temperatures rise, while dandelions are perennials and go dormant until cooler conditions arrive.

Winter annuals are best controlled after germination and before establishing. Late October through mid-November is the recommended time to control weeds. Fall treatments offer several advantages over waiting until spring.

Fall treatments are most effective when the plants are young and starting their life cycle. Once weeds are established and beginning to flower, they may be stunted when treated but will complete their life cycle, setting seed to start the process again.

Spring treatments have unintended side effects as well. Products used to control broadleaf weeds vaporize. These vapors float easily through the air on a warm spring day and can travel for blocks.

Broadleaf herbicides are growth regulators. They kill the weed by increasing the growth rate. Simply put, the plant grows so fast it grows itself to death. The side effect is twisted, curled, puckered growth of the leaves.

This distorted growth during spring affects our desirable trees, shrubs and flowers as they experience rapid leaf development. As the tender new leaves unfold, the herbicide-laced vapors are absorbed by the leaf. The result is misshapen, twisted growth.

Herbicide injury is the most common plant ailment on our gardening hotline in late spring (913-715-7050 or garden.help@jocogov.org). Fall treatments don’t have these unwanted side effects. Trees and shrubs are heading into dormancy and are unaffected by the herbicide drift.

Germinating weeds in the fall are small, often less than the size of a dime. However, if you look closely, you will see them starting to emerge. Thin areas in the lawn are the most likely places to find them. A thick stand of grass and proper mowing are the best defenses against weeds.

Treatment options include liquids or granular products. Liquid applications have advantages over granular products for weed control. Better coverage over the area results in more effective control and easier-to-spot specific areas to treat. Spot treatments also reduce the overall amount of herbicides used.

Don’t expect quick results when treating in the fall. The germinating weeds may not show signs of dying right away. Instead, the weeds slowly fade away over the winter months. The ideal way to treat is over several days in a row, when highs are in the 50s. Cool sunny days are the best possible conditions, not only for the weeds to grow, but also to take in the herbicide.

Fall weed control has several advantages, and now is the time to act for a less weedy spring lawn.

Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Have a question for him or other university extension experts? Email them to garden.help@jocogov.org.