How to eliminate speedwell, not grass #745378 - Ask Extension


How to eliminate speedwell, not grass #745378

Asked April 20, 2021, 4:22 PM EDT

I have a lot of speedwell taking over my lawn. There too much to weed by hand. It is crowding out the grass in places. I'd like to get rid of it. What is the most effective means? Are there pesticides that will target this weed but not hurt my grass?

Frederick County Maryland

Expert Response

Take a look at this:

You can get herbicides containing 2,4 D which should kill speedwell but not kill your grass. Follow all label directions.

If you live in MoCo there are limits to your use of chemicals on the lawn.

See: OMRI Lists | Organic Materials Review Institute

I found three "natural" herbicides that are labelled to kill speedwell, may meet MoCo requirements and does not kill lawn areas: Fiesta, Bonide Weed Beater FE and Leonard Selective Broadleaf Herbicide. There may be others. Always read the label and follow directions.

These are new to me and I have no experience with them or how well they work. You may want to contact the Turf Center at the Un MD.

Leonard Friedman Replied April 20, 2021, 5:55 PM EDT
2 4 D is the primary active ingredient in Weed Stop which I applied twice in the last week using a hand pump sprayer, but the speedwell still looks as healthy as the grass. When should I see dying speedwell?
On 04/20/2021 5:55 PM Extension Foundation <> wrote:
peterblood3213 Replied April 20, 2021, 6:50 PM EDT

It should work in 1-2 days or less. There are several possibilities:

1. Do an internet search on "speedwell", IMAGES tab, to be sure it really is speedwell, and what type of speedwell.

2. Only one variety of speedwell is specifically listed in the instructions as one of the weeds targeted. You may have a different speedwell. If yes, confirm application rate, 2, 4 D concentration, temperature, etc.

3. It is possible the product you used was degraded due to improper storage (shelf life/age, temperature, subjected to freezing).

4. Spray again and wait another 2 days. If the speedwell is still 'happy and healthy', call the manufacturer's contact number on the product you are using and as ask them why it is not working. Maybe they will send you a newly manufactured substitute or refund your money. If they refund you, purchase another manufacturer's product containing 2,4 D and read the instruction before purchase to be sure speedwell is listed as a targeted weed (and see if there is a recent manufacturing date). If in doubt call the manufacturer and ask if speedwell will be killed and confirm how to use the product.

5. If all else fails, try using a different herbicide.

Leonard Friedman Replied April 20, 2021, 7:44 PM EDT

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