Lawn weed identification.

Asked March 23, 2020, 7:55 PM EDT

I have been trying to get rid of this weed in my lawn for two years. At first I thought it was crabgrass but it must not be because all the herbicides I have tried have been unsuccessful. Any help you can give me would be greatly appreciated.

Macomb County Michigan

5 Responses

Hard to identify from pictures. It looks like tall fescue which has leaves with distinct parallel veins. It is a perennial like normal lawn grasses and spreads by short runners that make it appear to be a bunch type grass. Crabgrass comes up from seed every spring so it would not be there right now.
It would require digging out the area to remove all tall fescue plants or using a herbicide to kill the area. Herbicides labeled to control tall fescue may not be recommended for use on Kentucky bluegrass lawns. The other options is to use a non selective herbicide which will kill the area and require total reseeding or sodding. This is done with glyphosate which requires a little over a week to work before reseeding. Your best action is to get a lawn care professional out to look at more closely than I can and to advise you on options that they have that homeowners do not, as far as herbicides. Please read any herbicide label for precautions and application rates.

Thanks for your response. I have had incidents of crabgrass growing in my lawn before and I do not believe this is crabgrass. This weed has been growing in my daughter lawn for at least two seasons. I have tried the best pre-emergent in the spring and have applied several applications of spray spot crabgrass killers with no luck. I have used spot crabgrass killers on my lawn on what I thought was crabgrass with very good success. So I think this is something different. In the summer then the grass is growing this weed grows much taller and faster than the turf does. From the many pictures posted online of all the types of norther weeds quack grass seem to look the most like it . But the only herbicide shown to control quack grass is Certainty Herbicide. (very expensive). Which is why I contacted Ask an Expert to help identify the weed. I hoped that pictures of the plant itself would make it easier.


You are right it is not crabgrass. Quackgrass would have very aggressive runners underground and it also has long auricles that wrap around the stem and I do not see either of these in the pictures. The characteristics that separate them require up close examination. Whether quackgrass or tall fescue they are both controlled in the similar ways. Certainty is labeled for control of both tall fescue and quackgrass and yes it would be easier to kill them with a herbicide that does not kill the wanted grasses. Even with Certainty it appears to require multiple applications according to the label and care should be take when using this product to follow directions carefully so it does not damage Kentucky bluegrass. A sample could be sent to the MSU Diagnostic Services Lab for better accuracy. Their website provides directions on how to take a sample that they would need and shipping information at:

I am very grateful for your quick response. I have looked at the link you sent me for plant identification and that's what I'll probably do. Once things start growing again I'll sent them the plant and wait for an identification and base the treatment on that.

Once again thanks for the help and information.

Be Safe..

Thank you and best wishes for you and your family!