# Light green grass patches.



## HSGoodwin33

I am trying to figure out what these light patches of grass in my lawn are? and how to get rid of them? They started to appear after I installed an irrigation system and seem to be getting larger and spreading. I notice them the most in the areas that get a lot of shade? Is it Poa Trivialis?


----------



## ScottW

Bright lime green color, in areas of shade especially if consistently moist, with those thin hairlike stems... looks to me like it could be poa triv. Sorry.

There aren't selective herbicides that effectively kill it AFAIK, although Tenacity will light it up temporarily. One that claimed activity against both poa annua and poa triv (Velocity) appears to have been pulled and replaced with a newer SP version that's only labeled for annua and not for triv. I know some people are trying various combinations of multiple selective herbicides that each have "some" activity against it, but I'm not sure on the current state of the art there. A lot of guys here will skip the foreplay and go straight to nuking it with glyphosate.

In many areas of the US this year the cooler wetter spring-like conditions lasted longer than usual, which resulted in explosions of triv. I had patches of it in shady sections of my back yard. I glypho'ed some of the areas in late summer/early fall (prior to partial reno) although that is not the ideal time to hit it, because it's not growing as actively. Mine is currently suppressed at least visually, and I'm going to try improving cultural conditions there such as better drainage, less/no watering (unavoidable when you've overseeded/reno'ed), better soil percolation, and see if that slows it down any. But ultimately I may cave in and nuke it depending on how next year goes.


----------



## Robpin

That first picture looks like bentgrass to me. Maybe @masshole could chime in, he seems to be the local expert in bentgrass.


----------

