What variety is your current desired grass? I live in the Pacific Northwest and have a mix of perennial rye/fine fescue in some areas. I've seen different answers that tenacity would harm the fine fescue. Personally I just nuke the creeping bentgrass spots with glyphosate (2 or 3 apps), after dead I string trim the spot down to the ground, then seed as you would on bare dirt. In fact I just did that very thing today. Doing that is much more work than going with a selective route! I do use tenacity on a large back yard with 5000 sqft of tall fescue, no problem doing that.

If I had a choice, I would definitely try to get seed down in the fall if you have enough time. Old rule of thumb is 45 days before first frost.

One more thing - pulling bent grass will leave viable roots intact and would probably haunt you next season.

 

I searched high and low On bent grass control. From what I have found, tenacity & glypho are the two options.

There's a few studies that I found on tenacity and what I learned was. Fall is best for control, rake weekly to remove material, it will probably take several season to get it under control.

I have a test plot in my side yard that was hit with tenacity, raked, and seeded/sprayed again after 2 weeks. A great deal of the bent came back up and I can't spray again for another week. I will try to hit 2-3 more apps this fall and might dormant seed this winter. I'm trying to see if tenacity only is really viable for control. I can say two apps and then seeding did NOT work.

My back yard has had 3 treatments and shows less regrow. It has not been irrigated but not sure if that's contributing to the reduced active growth of bent. I will get some pics.

 

Just wanted to give you my personal experience with creeping bentgrass and T-Zone SE.

The first time I sprayed the T-Zone, I blanket sprayed my front yard. I noticed and area that I had suspected was bentgrass having trouble growing and it really stayed a lighter green.

After reading the label, and some other things on the internet, I realized that T-Zone SE is not supposed to be used on bentgrass. So, I spot sprayed later in the year in our backyard. There is a spot, about 4'x4', there I know is bentgrass. Just to test, I gave a good spray to a half of that spot. Sure enough, it's dead. I kind of forgot I had even done that until I noticed the die-off. I think I probably sprayed a little more than the recommended rate of 1.5oz/msqft. But, I was spot spraying so I'm not positive.

I think it's the sulfentrazone in the T-Zone that did it.

Anyway, just wanted to let you know about this. I have a few spots in our yard that I may hit this week.

 

Just wanted to give you my personal experience with creeping bentgrass and T-Zone SE.

The first time I sprayed the T-Zone, I blanket sprayed my front yard. I noticed and area that I had suspected was bentgrass having trouble growing and it really stayed a lighter green.

After reading the label, and some other things on the internet, I realized that T-Zone SE is not supposed to be used on bentgrass. So, I spot sprayed later in the year in our backyard. There is a spot, about 4'x4', there I know is bentgrass. Just to test, I gave a good spray to a half of that spot. Sure enough, it's dead. I kind of forgot I had even done that until I noticed the die-off. I think I probably sprayed a little more than the recommended rate of 1.5oz/msqft. But, I was spot spraying so I'm not positive.

I think it's the sulfentrazone in the T-Zone that did it.

Anyway, just wanted to let you know about this. I have a few spots in our yard that I may hit this week.

Interesting. I know sulfentrazone can injure grasses, but it's approved for use in bentgrass, rather than being listed as a controlled species. Maybe the t zone mix is a secret sauce.

How long has it been since the bent was sprayed in your lawn? Have you inspected for any type of new growth? When did you apply?

I'd definitely be willing to order some t zone to try myself.

 

At this point I would just live with it for the rest of the season to late on Long island for a over seed even for perennial ryegrass. This winter read up on bent grass and come up with a game plan to tackle it next year

 

Interesting. I know sulfentrazone can injure grasses, but it's approved for use in bentgrass, rather than being listed as a controlled species. Maybe the t zone mix is a secret sauce.

How long has it been since the bent was sprayed in your lawn? Have you inspected for any type of new growth? When did you apply?

I'd definitely be willing to order some t zone to try myself.

Maybe it's the triclopyr? The only other two, I believe, are 2,4-D and dicamba.

It's probably been three months since I sprayed it. There's definitely still a dead spot, but I haven't really inspected it closely. I'll go take a look today and let you know.