Zoysiagrass is a turfgrass that makes an excellent lawn in the South, but can invade other types of lawns to become a weed. It grows more slowly than other turfgrasses, but is unusually dense and able to crowd out competing grasses. Zoysia grows farther north than other Southern grasses, surviving temperatures below 10°F. In the North, it may be dormant for as much as half the year.
Kill zoysiagrass by spot-treating the patches. Rake out the dead grass and spot-treat any remaining live grass. Repeat if necessary until all the zoysia is dead. Zoysia is tenacious, and will probably reappear the following year. If it does, repeat the treatment.