My experience with poa trivialis
is that Tenacity doesn't kill it. The blades of the trivialis may all die, but it will come back from the roots again during the next cool, wet season.
After trying various approaches over the last few years, I now have what I think is a workable plan, which is very similar to what ligrass describes:
Normally I Glyphosate at 2x strength and make sure to hit 6 inches past the border of the patch. Then I slice it out and remove the top 1-2 inches of the patch, refill with topsoil. This works but then you gotta plug and reseed a pretty big hole.
I did almost
the above on many patches in my front yard last fall. The poa trivialis
has not returned in those spots. Here is what I did:
- Glyphosate all poa trivialis you can recognize, plus 8 inches beyond the perimeter of any poa trivialis you can identify.
- 7 Days later, repeat the glyphosate treatment again on all the mostly-dead-looking poa trivialis.
- After the glyphosate dries (or a few days later if I didn't have time yet), cut out the dead poa trivialis with a sod cutter. Get rid of this evil sod. (I dump it way off in the woods on my property, far from the lawn!)
- Transplant in good sod (also cut with the sod cutter) from a "donor section" of my lawn.
- Water the transplanted sod as you would a new sod installation and enjoy the fact that the poa trivialis was eliminated in just a week, and won't be coming back!
Last fall, I did the above with a rented power sod cutter, as I had another project which required the sod cutter. For the future, I'm planning to purchase a manual kick-type sod cutter.
For future battles with poa trivialis
I'm setting up a section of my lawn which is less visible from the street and a good place to grow new grass from seed (actually, it's where I used to have a vegetable garden). I'm planning to call this section of my lawn "the sod farm" and will be setting it up so that it gets good watering from just 1 or 2 sprinkler heads, so that I can water it for seed germination in the fall without having to overwater an entire zone. This will be the "donor section" of my lawn, to be used to grow sod to replace any sections of the front lawn that are killed off and replaced to combat poa trivialis