Q. I used corn gluten meal as a 'weed and feed' in the Spring, and my grass looked great. But I did use some chemicals to control chickweed in the summer. What should I do to get rid of the chickweed without chemicals?
- ---Bill in Merion Station, PA
A: Two answers. The first is to use corn gluten meal again for your "fall" feeding. "Fall" in quotes because the ideal time to do this essential chore is mid-to-late August, which is technically the end of summer. It's the perfect time to feed cool-season lawns like bluegrass and fescue, and corn gluten applied at this time of year can prevent the germination of weeds like chickweed just as well as it prevents crabgrass when used in the Spring.
The second answer, of course, is to care for your lawn correctly. OK, kids—everybody sing along!: "Don't cut your cool-season lawn lower than three inches; only water deeply and infrequently; only cut with a sharp blade; never cut wet grass; and always return the clippings to your lawn."
Yes, as is the case with just about every so-called weed in a lawn, the answer is to focus on the lawn and not the weed. Especially this 'weed'. In one of his best-selling lawn care books, our turf grass expert Dr. Nick Christians' entry on common chickweed emphasizes that "it does not compete with well-maintained turf."
And no, Nick does NOT say pretty much the same thing about all lawn weeds. For instance, he says that it's much better to learn to love the brilliant and ephemeral color of wild violets than to try and get rid of them; and notes that some weeds—like quackgrass, Johnsongrass, Dallisgrass, and sedges—are "very difficult" to control.
Now, good cultural practices will keep even these 'worst weeds' out, but Nick warns that while you can eliminate 'easy weeds' like common chickweed after they show up, his advice on those others is to tear up the lawn and start over. Consider yourself warned!
But if chickweed is so easy to get rid of, why are we 'doing' it this week?
Two reasons. The first is that most people don't treat their lawns correctly, and so we actually get a lot of questions about common chickweed in lawns. The second reason is my mental health! Tough, established weeds are really hard to help people with—as we'll see in an upcoming episode when I foolishly take a listener's challenge and once again address the issue of Japanese stiltgrass…
Anyway, you may have noted that we're saying "common chickweed". There is another kind, called 'mouse ear chickweed', although it's a very different plant. The Latin name for mouse ear chickweed is Cerastium; common chickweed is Stelleria. Mouse ear chickweed is a perennial plant, while common chickweed is an annual. And mouse ear is small but upright, while common chickweed is a very low-to-the-ground prostrate creeper. But both plants produce very similar, small white flowers that Nick describes as "star like", and that's probably why they share most of a common name.
Despite its cute name, mouse-ear chickweed is tough—a clump-forming broadleaf perennial with hairy leaves that shed herbicides. Your best bet is to dig up as much as you can—in the spring for warm season lawns and late summer for cool-season turf. (If you have a clump-forming grass like fescue, be sure to overseed into a nice layer of compost right after removal to fill in those bare spots.) And then be sure to water properly; no overwatering and/or frequent watering. Yes, back to the basics again; you can't treat a lawn incorrectly and not expect weeds to move in.
So what about common chickweed?
It might be the single easiest weed to pull from wet soil—which is where it tends to grow. So people who have decent drainage but are watering their lawns more than once or twice a week—or watering despite adequate rainfall—can often get rid of it just by letting the lawn dry out; which also forces the grass roots to grow deeper and crowd out weedy competition.
People who DO have terrible drainage should have their lawn core-aerated with a machine that pulls out plugs to relieve soil compaction; in the spring for warm-season grasses; fall for cool-season varieties. And cut at the right height! For cool-season grasses like fescue and bluegrass, that means never cutting lower than three inches. That's how I handle my "lawn" (in quotes because I don't worry about exactly what its composed of; just that it looks nice and green) , and I've never seen chickweed in it—although it does show up in my raised beds.
But I don't consider it a problem there. I let it act as a living mulch to keep out really bad weeds, and I pull a lot of it up to mix with the shredded fall leaves in my compost piles; it makes a terrific 'wet green' nitrogen source to help the leaves compost faster. And during the growing season, those tiny white flowers are just the right size to attract some of the best beneficial insects—and the smallest, most delicately beautiful native bees I've ever seen. They look like they've been dipped in gold!
And, as we pointed out in a Question of the Week several years ago, common chickweed is wonderfully edible; famed forager "Wildman Steve Brill" says that it tastes like 'a combination of corn on the cob and bean sprouts'. And medicinal plant expert Dr. Jim Duke ("The Green Pharmacy") adds that the plant contains potent natural anti-inflammatory compounds—especially if you pick and eat it before the flowers open.
And, as we said at the top, if you DON'T want to eat or otherwise utilize it, using corn gluten meal for your 'fall' lawn feeding in the late summer will greatly reduce its future numbers. Common chickweed is a 'winter annual'; that's a plant that dies completely over winter, but before it dies, drops a lot of seed in the early fall. As we explain in detail in a previous Question of the Week, a well-timed application of corn gluten meal towards the end of summer can prevent germination of those seeds—AND the seeds of some more tenacious weeds as well.