Brown patches in lawn
Hello, The link below provides photos of brown patches found in my neighborhood's common area. Unfortunately, one of the brown patches is creeping towards my backyard lawn. Can you assess the cause of the brown patches and instruct me on what I can do to prevent the brown patch from infiltrating my yard? https://goo.gl/photos/r5exBn2rq9ksSgiw9 Thank you,
Montgomery County Maryland
We can't be entirely sure from your photo, but our hunch would be that this is nimblewill, which is a grassy perennial weed. The patches slowly enlarging with creeping stolons.
Here is our weed i.d. page. Click on nimblewill and see if it's a match during the growing season: https://extension.umd.edu/hgic/lawns/lawn-weed-identification#grassysummer
Some control options are listed there.
If your yard is across the driveway it can't creep to you, which is the most common method of reproduction. If it goes to seed, it could seed into your yard, but that is less likely. Keep watch and pull it right away if you see it. The same pre-emergent products that work for crabgrass will also work for nimblewill.
If you needed to eradicate big patches like in your photo, you would need to use a non-selective weed killer containing glyphosate to kill everything back and reseed the area. That would best be done in late summer into early fall.
Many weeds can be deterred by having a healthy, thick lawn. Here is our lawn page: https://extension.umd.edu/hgic/plants/lawns