Invasive grass?

Asked November 5, 2018, 7:45 AM EST

I have a sodded lawn which is about 30 years old. This summer I started noticing a lighter color of grass growing in patches all over my lawn. Many people in my neighborhood have the same issue. Any advice?

Oakland County Michigan grassy lawn weeds

1 Response

Hello,

This looks like either creeping bentgrass or annual bluegrass. These often get started when plants cling to lawn service equipment and it is dropped in the neighborhood.

In any case, there aren’t many herbicides specific to these grasses, that won’t kill your desirable lawn grasses.

So, digging out the patches and replanting or sodding the patch; or using a non-selective herbicide ( one that kills everything), like glyphosate, to kill that patch and then reseed or sod, are two choices for control.

Here is a site to which you can compare closeup samples, and try to see which grass you have. The ‘control’ tab will specify which herbicides can control each grass:

http://www.msuturfweeds.net/details/_/creeping_bentgrass_42/

http://www.msuturfweeds.net/details/_/annual_bluegrass_47/

The whole website that covers other common weeds is www.msuturfweeds.net

If you use a herbicide, always read and follow all precautions on the label. The label will tell you how long you must wait before replanting. Reseeding or sodding can be done in spring.

If you will be using seed, do not use a pre-emergent crabgrass killer on the patches. For seed, get fresh seed (look for a date on the bag), get good seed to soil contact, and keep it constantly moist until it is ready to mow at 3 inches high- usually 4-6 weeks.

For sod, call your supplier and ask when their sod shipment comes in. Go that day and pick up sod, then immediately cut it and place it in the prepared patches- again good sod to soil contact is necessary.

Here are some references, should you need them-

https://www.canr.msu.edu/resources/establishing_a_new_lawn_using_seed_e2910

http://www.canr.msu.edu/news/tips_for_reseeding_lawns_in_the_spring

http://msue.anr.msu.edu/uploads/files/e2911.pdf

If you can’t ID the grass from the above website, you can take a 6 inch by 6inch sod sample ( with roots attached) to MSU Oakland county extension office for ID. If he grass has any seed heads on it, that would be even better. Call first to determine when they are open and available, since they are on winter hours right now-

https://www.oakgov.com/msu/mg/Pages/garden-hotline.aspx

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