Dorothy is a Master Gardener, former newspaper reporter, and the author of several books. Michael is a landscape/nature photographer in NM.
It's Invasive, Unattractive, and Everywhere
Crabgrass, a summer annual grassy weed, seems to be one of the most ubiquitous weeds around. It relentlessly takes over a yard with no remorse. Adverse conditions cause it no pain so you can't really depend on Mother Nature for assistance. Learn to fight it yourself; the win will be oh-so-worth your time and energy.
Perfect for Pulling
Learn to Identify Crabgrass
Crabgrass lives up to its name; it resembles a crab with many legs that hug the ground. Those legs are actually long stems or branches with pairs of leaf blades, and that hugging it does makes it impossible to mow away.
If you have thin or bare spots around your yard, crabgrass will consider you its new best friend and will set up residence in those areas. Those weeds that you find so often growing out of the cracks in your driveway or sidewalk are probably crabgrass. I'm telling you...it is relentless.
Young crabgrass is a bright green, which up against a deep green lawn, makes it easy to spot. But, after it grows older, it turns a darker green. It likes to get an early start in the growing season, so you have to be vigilant as well.
Crabgrass, once mature, will turn a reddish/purple color near the base, which makes it easy to tell the difference between it and other grasses or weeds.
Prevent Crabgrass From Sprouting
If crabgrass has been a huge problem for you and you haven't been able to get the results you want, you may need to apply a preemergent herbicide designed to selectively control crabgrass. Preemergent herbicides must be in place before crabgrass seedlings and other weeds begin to emerge. Most will not kill crabgrass that has already emerged; they have to be applied and watered in to develop that herbicide barrier before weed seed germination.
My personal choice for a preemergent herbicide is Jonathan Green Corn Gluten Weed Preventer. It works by stopping crabgrass before or during germination so that it never has the chance to come up, and it's all organic (in case you are as environmentally conscious as I am). If you can stop these invasive weeds this way, you’ll spend less time pulling weeds or treating your lawn with post-emergent herbicides later.
Before you buy any herbicide, READ THE LABEL and use it as directed.
Preemergents don't guarantee instant gratification but they do work effectively to reduce weeds springing up in your yard when used properly.
- Unsure when to apply your preemergence application? I suggest you err on the early side. You may lose some effectiveness but you'll still kill a lot of crabgrass. If you apply it too late in the season, you are likely to miss some early sprouts.
- Don't let the calendar determine when to apply the herbicide. Pay attention to your landscape and apply when the soil's surface is about 55 degrees Fahrenheit.
- Mow your grass high to reduce infestations of crabgrass.
- Unless your entire lawn is infested, apply the herbicide only to problem areas or several feet beyond (reduce the use of chemicals whenever possible). Make sure to apply it in the areas where the crabgrass thrives, such as next to driveways and walking paths.
- Don't seed lawns that are treated with crabgrass killer. The products will also prevent the good grass seeds from sprouting.
Yank it While it's Young
Pull out young crabgrass the second you spot it. The young plants will only leave a very small hole in your yard and your desirable grass should fill it up quickly. Pulling it in its early stage is an effective way to get rid of it.
If the weed has pushed up several rows of leaves, look at it very carefully. If you see a slender, green seed head that is still closed and folded up against the leaves, pull it too.
If the seed head tines have spread out like a fork, you should leave it alone, since disturbing it will scatter scads of seeds right over the huge hole you created when you removed the mature weed and your efforts will have been in vain (you have just planted some new crabgrass). Wait until fall when the crabgrass will die off on its own, and seed any bare or patchy areas to allow your good grass to crowd out the crabgrass seeds.
- Crabgrass plants that are ideal for pulling has 3-4 sets of leaves but no splayed seed heads.
- It's still good to pull immature crabgrass plants that have tight, green seed heads.
- If your crabgrass has splayed seed heads, you'd be wise to simply leave it alone. Pulling it will leave a big hole in the lawn and spread thousands of seeds per plant. It will die anyway in the fall, and in the spring you can apply a preemergence herbicide to keep the seeds from sprouting.
- Remove the crabgrass before it disperses its seeds. Win the battles, win the war!
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2020 Mike and Dorothy McKenney