Whether you, a previous owner installed it, or a neighbor has it in their yard and it is now making it's way across your lawn, you know how unsightly Zoysiagrass can be in cooler areas of the country. Long before winter sets in, Zoysiagrass has already turned a straw-brown and remains that way long after the cool season grass has turned a lush green.
If you live where cool season grasses are the norm and have Zoysiagrass in your lawn and you want to get rid of it, here's a few tips that might help. But be warned, it's not pretty or easy.
In late summer, typically around early August, you have to begin the process. It requires killing the entire lawn with a non-selective herbicide. You have to be careful with this as it will kill desirable plants as well. Spray on a calm day, and FOLLOW LABEL DIRECTIONS CAREFULLY. Apply the herbicide evenly and consistently so you don't miss any spots.
This step one should turn everything into a straw brown. Once it has died back, mow the dead lawn as low as possible (1/2" if possible). Wait for 2 - 3 weeks. Zoysiagrass will begin reemerging. Wait another week and reapply the herbicide again to any of the new growth. Wait another two weeks and again reapply the herbicide if you see any new growth.
After going through the herbicide and wait process 3 times, it is now time to begin the renovation process. You don't need to remove the dead grass. Leave it in place. If you have compacted soil, aerate heavily. Then re-seed and follow label directions on the seed.
If you don't have compacted soil, you can use a slit-seeder that cuts small slits in the soils surface and drops the seed into place. Run it left to right once and then top to bottom.
Another option is to remove the sod with a sod cutter. Include a small layer of top soil if possible. This will work for either small or large areas. Once the sod is removed, wait several weeks to make sure no new seedlings emerge. If they do, use high strength Roundup. After the 2 weeks, either reinstall new sod, or add top soil and till in with existing top soil. Re-seed.
If after reading this, you've decided to live with the Zoysia and all of it's nasty habits, you can always hire a professional to do the job for you. Pros have a lot of experience renovating lawns and can handle just about any problem that arises. By the end of October, you should have a beautiful lawn that will only improve next season and the season after.