Since you are located in CT, I would recommend waiting until August to do the kill unless they want to go the whole Spring seeding route. I've sprayed areas with fully established Meyer Zoysia with Roundup Super Concentrate (50% active ingredient - the purple cap variety you can get at home depot) and it smoked the area - dead dead - blades, stolons and all.

If they are concerned about it coming back next Spring or Summer, treat the area you nuke this year, the following Spring with Tenacity (Scotts Starter Fert + Tenacity) and it will stop / slow any survivors the following year. 2-4d will also put a major hurt on it when it is breaking dormancy. The good news for them is, since Zoysia is such a slow mover, and you are in 6b, they will probably not have to repeat this treatment for a long time (like 10+ years), unless they are surrounded by other neighbors with it.

At this point, my backyard is primarily Meyer Z52, and my front yard is a typical northern mix of TTTF/KBG/PR. I've used this method to nuke the Meyer areas from encroaching on the front yard and also keep my adjoining neighbor's Zoysia lawn out of the front area.

 

I killed mine off last July with just Gly. We'll see if it returns this year, but I doubt it. I'll be treating the area with Tenacity as well.

 

Good ideas, both of you. Obviously, nothing is going to be done until it's green and growing (in May) at the earliest. I'm going to have him measure the area now while it's brown and record the dimensions so we know where to spray. No way would I have him try to seed in the middle of Summer...but maybe plugs and then seed later on in August.

The advice to continue using Mesotrione the following year is a good one.

If glyphosate is adequate, great. That will be nice and simple.

 

Good ideas, both of you. Obviously, nothing is going to be done until it's green and growing (in May) at the earliest. I'm going to have him measure the area now while it's brown and record the dimensions so we know where to spray. No way would I have him try to seed in the middle of Summer...but maybe plugs and then seed later on in August.

The advice to continue using Mesotrione the following year is a good one.

If glyphosate is adequate, great. That will be nice and simple.

Make sure he kills beyond the area he is currently seeing as well just in case there are any runners hiding in his cool season turf.

 

I want to to the complete opposite. My backyard is mostly zoysia with mixed cool season grass mixed in. I want to kill the cool season now with roudup while zoysia is dormant. Then this summer fertilizer on zoysia to get it to spread the small gap's. Does round up kill zoysia while it's dormant?

 

I want to to the complete opposite. My backyard is mostly zoysia with mixed cool season grass mixed in. I want to kill the cool season now with roudup while zoysia is dormant. Then this summer fertilizer on zoysia to get it to spread the small gap's. Does round up kill zoysia while it's dormant?

If the turf is fully dormant, it would be safe, however, I strongly caution you on doing it this year. It's been an unusually warm winter for this part of the country and it's likely Zoysia is beginning to wake up. The existing blades may still look dormant right now, but if you get in close to the root / runner areas, you might see signs of activity. Personally, I wouldn't risk it, because if it is waking up and actively growing in any way, you will surely kill or damage it.

I think a better bet for you this year would be to use a selective herbicide which can remove cool season turf from warm season turf. There are quite a few options there, but I have not personally used any of them. If you have success with them this year let me know, because in my backyard, I'm looking to do the same thing (expedite the takeover process). I've been mowing low and frequently to promote the takeover in a natural way for the time being.

 

Killing off 25% of my backyard (about 5k in all) this summer to knock out some Zoysia and seed tttf in the fall. Been waiting a couple years to do it and I can't wait! Hate looking at that brown for so many months.

 

I want to to the complete opposite. My backyard is mostly zoysia with mixed cool season grass mixed in. I want to kill the cool season now with roudup while zoysia is dormant. Then this summer fertilizer on zoysia to get it to spread the small gap's. Does round up kill zoysia while it's dormant?

If the turf is fully dormant, it would be safe, however, I strongly caution you on doing it this year. It's been an unusually warm winter for this part of the country and it's likely Zoysia is beginning to wake up. The existing blades may still look dormant right now, but if you get in close to the root / runner areas, you might see signs of activity. Personally, I wouldn't risk it, because if it is waking up and actively growing in any way, you will surely kill or damage it.

I think a better bet for you this year would be to use a selective herbicide which can remove cool season turf from warm season turf. There are quite a few options there, but I have not personally used any of them. If you have success with them this year let me know, because in my backyard, I'm looking to do the same thing (expedite the takeover process). I've been mowing low and frequently to promote the takeover in a natural way for the time being.

Thanks for the info. Dug into the zoysia and yes there's activity it's waking up. Time for a new game plan.

 

I want to to the complete opposite. My backyard is mostly zoysia with mixed cool season grass mixed in. I want to kill the cool season now with roudup while zoysia is dormant. Then this summer fertilizer on zoysia to get it to spread the small gap's. Does round up kill zoysia while it's dormant?

If the turf is fully dormant, it would be safe, however, I strongly caution you on doing it this year. It's been an unusually warm winter for this part of the country and it's likely Zoysia is beginning to wake up. The existing blades may still look dormant right now, but if you get in close to the root / runner areas, you might see signs of activity. Personally, I wouldn't risk it, because if it is waking up and actively growing in any way, you will surely kill or damage it.

I think a better bet for you this year would be to use a selective herbicide which can remove cool season turf from warm season turf. There are quite a few options there, but I have not personally used any of them. If you have success with them this year let me know, because in my backyard, I'm looking to do the same thing (expedite the takeover process). I've been mowing low and frequently to promote the takeover in a natural way for the time being.

Thanks for the info. Dug into the zoysia and yes there's activity it's waking up. Time for a new game plan.

I hate saying this because I've been trying to eradicate zoysia for years, but here goes:

A couple of things you could do to encourage the zoysia is the same thing in reverse when I try to encourage the kbg.

For zoysia, don't fertilize in the early spring. Wait until the zoysia is actively growing to make sure it gets the fert (look up the warm season guide for the best info). Cut the lawn short. It's harder on the kbg, but the zoysia likes it (1.5-2"). Go lighter on the water in the summer, so the kbg struggles. The zoysia won't stress nearly as much up here in the north. Don't fertilize after 9/15. The zoysia will start towards dormancy and the kbg will still be growing and this is the best time to fertilize kbg. Once the zoysia goes dormant (probably totally dormant by 11/15), you should be able to nuke the cool season grasses.