The fall season and even some of the milder weather periods of early winter present great possibilities in weed control, particularly if you are interested in using recommended herbicides. Any time of year is appropriate to hand-remove weeds for common lawn weeds such as dandelion and plantains. However, hand-removal of creeping weeds with fibrous root systems is often very limited in success and can be quite frustrating. In these cases, herbicides are often the most effective option in control.
What does the season have to do with control? There are a few major reasons:
- Many of our most problematic weeds home lawns are cool-season broadleaf perennials, and fall is a time when they are actively growing and translocating food and water throughout the plant. Perennials (plants that live for 3 or more years) are some of Mother Nature’s hardiest, most durable plants, and in order to control them with a herbicide, it is important to get the chemical translocated throughout the entire plant in order to control growing points beneath the ground as well as above. Weeds such as dandelion, plantains, wild violet, creeping Charlie, mock strawberry, and even the ‘grass-like’ weeds of wild onion/wild garlic are ideally treated with appropriate broadleaf herbicides in the fall.
- Tolerance levels of most broadleaf landscape plants (i.e. trees, shrubs etc.) to potential exposure to a broadleaf herbicide are quite high in the fall because these plants have been ‘hardened-off’ by the stresses of summer. In contrast, these same plant materials are usually very sensitive to the same herbicides in spring applications when the desirable plants are loaded with very succulent plant tissues that are just emerging and developing.
- Fall is an ideal time to control the majority of winter annual broadleaf weeds that emerge from September through mid-October. Plants such as henbit/deadnettle, chickweeds, and buttercup are prominent winter annual broadleaf weeds that can easily be controlled by herbicides when they are young and actively growing.
The most common herbicide choice is a general purpose mixture comprised of two or three of the following individual herbicides or active ingredients: 2,4-D; MCPP (mecoprop); and dicamba (Banvel). Multiple active ingredients will control a wider spectrum of broadleaf weeds, than a single active ingredient.
Source: Virginia Tech Cooperative Extension “Fall Lawn Care”