white dutch clover

Asked January 30, 2014, 6:12 PM EST

I have areas of my lawn that we can never get good weed control. Other parts have nice grass coverage. Could I seed over the weedy areas with dutch clover to crowd out the weeds and then till it under and reseed the area, or will it spread to my entire lawn crowding out the existing grass? I hate that we use chemicals to control weeds and am searching for an alternative.

Adams County North Dakota

1 Response

I agree with you -- I hate to use toxic chemicals in my yard. On the other hand, lawn herbicides are incredibly effective tools. I think the key is to use them judiciously. Use them when they are most effective, and only when absolutely necessary.

There are a few issues to deal with:
Why are weeds dominating an area of your lawn? Is it a wet area? Dry area? Is the soil infertile? Too salty?

What types of weeds are you dealing with? Are they perennial (long-lived, more than 2-year-old) weeds like dandelions and thistles, or annual (1-year-old) weeds like crabgrass and foxtail?

I don't think clover is a particularly aggressive weed and I don't think it will have the desired effect you are looking for. Clover is a legume -- it can produce its own nitrogen from the air -- and it typically is a dominant plant only when the soil is naturally infertile.

So to answer one of your questions: I don't think clover will take over your lawn unless your soil is very infertile. On the other hand, I don't think it will completely suppress your weeds either.

This is what I recommend:
Early this spring, let's take a soil test and find out what is going on with the soil. Each test will cost $18. You could do a soil test in the area of your lawn that is struggling and compare it with a soil test done in the area of your lawn that is flourishing. I did this in my own yard and discovered the area in my lawn that was struggling was much more alkaline and had a high salt content. In the long run, a soil test is a good investment. This service is offered by your local county Extension service.

You need to know your enemy. In this case, you need to know what weeds are causing the problem. If these are perennial weeds, I would spray them with glyphosate (tradename Roundup) in spring when the weeds start to grow. The weeds will die within two weeks. Then work up the soil and sow a quality grass seed mix. Before sowing, you may need to fertilize the soil, depending on what the soil test analysis says.

If these are annual weeds, you could wait for them to germinate In spring and then spray them with glyphosate. Or, you could just go ahead and cultivate the soil in spring and sow grass seed. in this case, we can focus on controlling the annual weeds next spring.

Once the turf gets growing, you need to take care of it. The best defense against emerging weeds is a healthy and thick turf. Cut your turf tall -- this will shade out the emerging weeds. Fertilize every fall -- this is when turf roots grow and you get the most bang for your fertilizer buck. You can fertilize more if you want, but this is up to you.

If you use herbicides, spray them when they are most effective. This is in mid to late September. At that time of the year weeds naturally channel their foods down to their roots to prepare for winter. If you spray in fall, the weeds will naturally absorb the herbicide from their leaves and send it down to their roots. This is good news for us since the weeds will die completely.

That's my recommendation. I love clover (heck, I'm Irish), but a much more effective strategy will be to understand why the turf won't grow in one area (bad soil, too shady, poor drainage) and then correct the problem. A one-time spray of glyphosate will kill the weeds this spring and give you a blank slate to start a beautiful lawn. Fertilize in fall. Spray weeds in fall, if needed.

If you have specific questions or more specific information on the weeds, please get back to me at my e-mail address below.