Raise the height of cut to 3 inches or higher. After several years, this type of management encourages the cool-season turfgrasses to overtake the zoysiagrass. Faster elimination is possible. You would have to kill the entire zoysia lawn with a non-selective weed killer, then renovate and reseed. There has been increased use of zoysiagrass by homeowners on Long Island over the years.
Some people are happy with it, while others are quite disappointed.
More is known about it than was known 25 years ago, but much more is still to be learned. Research is needed on the use and maintenance practices of zoysiagrasses in combination with cool-season grasses. Such combinations might give better turf throughout the year. New varieties are also needed which are not straw colored as long during cool weather.