Most of us would like to rid our lawns entirely of weeds because weeds are downright ugly and they ruin the overall appearance of our yards.
However, aside from their unattractive appearance, weeds can cause problems due to their aggressive behavior. They will compete with the grass and other plants for water, sunlight and nutrients, and over time they will kill desirable grasses. It’s a game of survival of the fittest – a game that weeds are more adapted to win.
Learning more about where weeds come from, and why they keep coming back, should help you in your battle to maintain a weed-free lawn.
What is a weed?
A weed is basically any plant that is growing out of place, either in the lawn or a garden area. The most common weeds found in lawns are dandelions, clover, ground ivy, crabgrass and dollarweed.
Some weeds, such as crabgrass (see picture to the left), are annuals which means their life cycle lasts one year. Basically, they grow, produce seed and then die. They can produce hundreds or even thousands of tiny seeds, which lay dormant until the following spring when they re-emerge as new plants. Many other grassy weeds (called monocots), such as goosegrass and quackgrass, produce seeds in a similar fashion.
Those seeds will sprout again the following spring – often producing a larger crop than the previous year. Over time, the problem gets worse and worse, and the weed will eventually crowd out the “good” grass.
The other type of weeds most commonly found in lawns are perennial weeds, which include most of the broadleaf weeds (called dicots), such as dandelions and spurge. Dicots typically spread by both seed and underground shoots, or runners. For example, a dandelion will spread underground and send up shoots that develop into new plants. As each new dandelion plant matures, it develops feather-like seed heads that spread to new locations by blowing in the wind.
Those weed seeds will establish in a new location, if – and only if – they can find a place to lodge. Even a cement patio will have weeds growing up from the cracks. That is why weeds are so hard to control — they can grow almost anywhere!
Broadleaf weeds, once established, don’t give up without a fight. You can pull them up, blow them up, cut them up…it doesn’t matter because they will grow right back, unless the entire plant is removed or destroyed. The problem is, however, that dandelions and other broadleaf weeds, have a deep tap root that can grow up to several feet deep in the soil, which can be almost impossible to dig up. Witness the following situtation:
- Tired of dandelions, this gentleman decided to just blow them up…
- After blowing a hole in his yard, he checks to see if the dandelion is gone, and it appears to be…
- A couple of weeks go by, and the weed is back!
- The dynamite must not have killed the root.
Getting Rid of Weeds
So how does a homeowner stop these weeds from ruining the lawn?
The first step is to apply a pre-emergent to the lawn and garden areas in the spring. This will create a barrier that prevents the hundreds of weed seeds that annual weeds drop in the fall from emerging as new plants in the spring. This is a great way to control grassy weeks like crabgrass.
However, if you didn’t apply a pre-emergent in the spring and grassy weeds are taking over your lawn, you can apply a selective herbicide that is especially designed to kill weeds like crabgrass, and not the grasses in your lawn. For crabgrass and other grassy weeds, use a crabgrass killer for lawns. Other options include digging grassy weeds up by hand, or waiting until next year to apply a pre-emergent in the spring.
Perennial weeds, like dandelions and thistle , are more difficult to control because of their strong tap root that can often grow as deep as three feet. The easiest way to eliminate them is with a selective herbicide product that is safe for your lawn, so you don’t harm your grass. A selective herbicide means it is intended to kill a certain plant, as opposed to a non-selective that kills all vegetation.
For example, weed killer for lawns will kill the entire weed, but not the grass, all the way down to the root so the entire weed will die. In the image shown here, the green circle shows the area in the middle of all those dandelions that was sprayed with weed killer for lawns.
You can also apply a weed and feed product, as your lawn application in the spring. Whatever product you apply, be sure you read and follow label instructions carefully.
For a lawn that is full of weeds, you may want to consider applying a non-selective herbicide to kill the entire lawn and start over from seed.
Your Best Defense
There is no doubt that a thick, healthy lawn is the best method to a weed-free lawn. You’ll recall that weed seeds can grow almost anywhere — they only need a place to lodge in the soil.
A thick lawn won’t allow any room for weed seeds to lodge, and a healthy lawn will steal nutrients and water away from any weeds that try to establish in the lawn. A healthy lawn also can withstand dry periods and insects, which is why an annual program of regular feedings is so important to the overall health of a lawn.
And it is easy to recognize a healthy lawn – it is the one without weeds in it.