How to Control Weeds in Your Lawn
By: Julie Day
The first time my lawn erupted into a sea of purple violets, I actually rather liked it – I tend to evaluate a plant’s beauty first before sealing its doom by calling it a “weed.” For the most part, however, gardeners prefer for their turf grass and their flowers to stay in their respective places and for weeds to stay out of the picture altogether.
While fighting weeds is a year-round job, weed prevention is best practiced in the fall and early spring to take advantage of the growing season of turf grasses. A healthy, thick lawn is your number one defense against weeds. In fact, a badly weed-infested lawn is usually a sign of nutrient imbalance or other soil problems.
For a nice, green lawn that is free of weeds, focus first on getting your grass healthy, then give it a couple of months to become strong before applying weed control products. Minimize turf areas, so that you’re only growing grass where grass easily grows. A small patch of healthy grass is far more attractive than a huge expanse of thin, weedy lawn.
Clover, while good for the soil, is a frequent lawn-invader.
If you’re amending your soil or sowing new grass seed, buy high-quality seed and consider mixing your own soil amendments using only the best ingredients. Pre-mixed topsoil from landscape supply yards often contains weed seeds.
Small patches of weeds can be handled by pulling or digging. All-over lawn weed control is usually not necessary either, as a heavy infestation would be better handled by making the grass healthy. However, for those in-between situations, you may want to consider the use of a chemical or organic herbicide.
Smartweed (polygonum sp.) can take over poorly-drained, moist areas
To choose the correct herbicide, it’s helpful to understand some basic terms that appear on the labels of commercially-packaged weed control products.
- Total vegetation herbicides kill all plants and sterilize the ground for a certain period of time – they should be used very carefully.
So how do these terms work together when shopping for herbicide? Here are some common examples:
- Trifluralin (contained in products such as Preen Garden Weed Preventer), on the other hand, is a pre-emergent, nonselective herbicide that will kill grass seeds as well as weed seeds and is only for use in established gardens.
- Combination Herbicides (such as Ortho Ground Clear) contain more than one post-emergent, nonselective herbicides (such as glyphosphate and imazapyr). Imazapyr is very slow to break down, so this product is designed to kill every plant it contacts and to keep the ground sterile for up to one year.
As with any chemical product, follow package instructions carefully, and only use if absolutely necessary. Herbicides can affect surrounding plants and can pollute ground water when used improperly or in large quantities. By carefully selecting the correct product, you can get rid of those pesky weeds in no time.
My purchased potting-soil often includes “bonus” morning glories.
For more on dealing with weeds in your lawn:
- How to Have a Weed Free Lawn (article)
- Lawn Weed Control (video)
- How to Control Crabgrass (article)
- How to Control Dollarweed (Pennywort) (article)
- How to Control Dandelions (article)
- Vinegar Weed Killer (video)
- How to Target Weeds (video)
For help identifying garden weeds:
- Weed Identification Guide (Virginia Cooperative Extension)
- Common Lawn and Landscape Weed Identification (Landscape America)
For detailed information about specific weeds and control methods: