Lawn Weed Identification

Asked May 7, 2020, 12:21 PM EDT

Hi - This grassy weed is starting to invade my fescue lawn. Any idea what it is and what type of turf friendly herbicide I can use to eradicate it? Thanks.

Sussex County Delaware

5 Responses

I believe it is roughstalk bluegrass (Poa trivialis). Before I commit to this can you answer a couple questions for me? Tell me about the site in question. Is it wetter than other areas? Ie: near a downspout, or a low sunken area? And, is the area shaded at all? Could you post a closer picture of the base of the plant and the tip of the leaf blade please? After your answer I will provide you recommendations for control. Thank you!

The majority of the breakout is in an area that is lower than other parts of the lot. However, there are random spots throughout the yard. The majority area has morning shade this time of year (3-4 hours) and has more shade throughout the winter when the sun is lower.

Roughstalk blugegrass can spread pretty aggressively if left unchecked. My best recommendation is to spray glyphosate on the patches to kill them and then reseed the areas you sprayed. I would recommend to mix in some fine fescues if shade is an issue. Early morning sun is most important for turf. So, the fine fescues tolerate shade very well and will perform much better in the morning shaded areas. When I say fine fescue is am referring to a group of grasses. The names you will see on seed bag labels will be "chewing fescue", "red fescue", "sheeps fescue', and/or "red fescue". Any combination of the fine fescues will work in this situation. Adding any of these fine fescues to a Kentucky bluegrass/tall fescue mix would be an ideal seed mix.

Thank you. So, it sounds like there is no turf friendly herbicide to treat this, correct? Should I wait until fall to do this since it requires over seeding?

Unfortunately, there is not a good solution other that glyphosate and reseeding. There is a herbicide named Velocity, but it is very difficult to apply due to such low rates. It is nearly impossible to apply correctly with out a ride-on sprayer. Not to mention, it can cause unwanted and undesirable turf damage to your current stand of grass. Only turf professionals should ever consider using this product.

Yes, I would wait until fall to spray and reseed. I would spray the patches with glyphosate in mid to late August. Then 10-14 days later you can begin seeding the sprayed out spots.