Golf Coarse Grass Patches
I had a beautiful lawn the last few years but this year I have invasive grass patches everywhere. The patches look like golf coarse green or fairway grass, dense and spongy with a bluish-green almost turquoise color to them. Our lawn is a mix of Kentucky bluegrass, red fescue, and a couple rye grasses but I have never seen this type of grass before. Could someone let me know what type of grass this could be, if it’s a grass at all, and how to get rid of it? I’ve attached pictures below. Thanks!
Jackson County Michigan
It appears to be creeping bentgrass but can't be determined positively from this vantage point. Read more here: http://www.msuturfweeds.net/details/_/creeping_bentgrass_42/
The first necessity is a positive ID before any treatment considerations. You can
send a sample patch to Diagnostic Services for identification https://www.canr.msu.edu/pestid/ or involve a professional lawn care company.
While there are other invasive grass possibilities treatment is often the same using a non selective herbicide to kill it off with reseeding to follow.
Non-selective Chemical Removal - Glyphosate. (Roundup or similar) Use a non-selective herbicide that contains glyphosate to kill the patches. Keep in mind that non-selective means that it kills whatever plants it touches. This method will create dead patches that can be re-established. You will need to make at least two applications. Make the second application 14 days after the first. Seven days after the second application you can rough up the area and sow your new grass seed.
Selective Chemical Removal - Until recently, none were available. Mesotrione is the only labeled active ingredient for the selective control of bentgrass in other cool-season grasses. As with other selective grass controls, it requires multiple applications per season. The most effective control is achieved from 3-4 applications applied 14- to 21-days apart.