Many KC homes built in the late 50’s-early 60’s were planted to Zoysia. This grass is native to Korea and other parts of Asia where their climates are similar to our Kansas City transition zone climate. Zoysia was promoted as a low maintenance grass, but over time has proven to have its share of issues.
Unlike bluegrass, fescue or ryegrass (cool season grasses), zoysia is a warm season grass that is heat tolerant and grows best in summer. Bermuda and buffalo grass are closely related to zoysia and have similar growth habits. Kansas City lawns that started out as strictly zoysia have mixed with cool season grasses since zoysia does not tolerate shade or has died for other reasons related to insects or disease. The information below is about maintaining a zoysia lawn in Kansas City:
Dormant zoysia should be mowed as low as possible to remove the dead leaf tissue. This is a messy job and may require bagging or mowing 2-3 times to finely chop leaves for quicker breakdown. This process gives a quicker and more uniform spring green-up. Zoysia likes short mowing of about 1 ½ inches during most of the summer. As the days get shorter increase the mowing height to 2 inches in early August. This gives the grass more energy for roots to survive the winter.
A crabgrass preventer can be applied in early spring but should not be a “weed and feed”. In other words, use a crabgrass preventer (Hi-Yield Dimension) without fertilizer. Zoysia is sensitive to broadleaf weed herbicides as it comes out of dormancy. As a result, it’s suggested that broadleaf weeds be spot treated as zoysia greens up in early-late spring.
Late May- early June- After full green-up, use Ferti-lome Lawn Food + Iron to encourage growth. Zoysia tends to produce a lot of thatch and this is an excellent time to either core aerate or verticut, then fertilize immediately after performing these operations.
Mid-July- Apply Ferti-lome + Iron again and this is the last fertilizer application for the year.
Chinch bugs and billbugs have been a significant problem the past several years. These insects do not like shade which means they normally damage zoysia receiving the most amount of sunlight. You may want to consider applying Ferti-lome Turf Ranger and possibly other insect control products. Treatments begin in early June and the lawn will most likely need multiple applications.
Billbug adults/ larvae Chinch bug growth stages
This disease is now widespread throughout Kansas City. Several university turf grass departments are coordinating efforts to understand this fungus that nevertheless remains difficult to control. Zoysia Patch resides in the thatch layer or clippings and is most active in fall and spring. When active, grass has orange colored patches from 1-10 feet in diameter. Infuse Fungicide from Bonide is labeled for this disease and preventative treatments are most effective applied about mid-September then again in mid-spring. In addition to fungicide applications, avoid mowing when grass is wet and try to minimize the thatch layer with regular core aerating or verticutting in early June.
Zoysia Patch Disease- Note Orange Color
Zoysia is a beautiful lawn when it doesn’t fight the problems mentioned above. Unfortunately this grass has had many challenges the past several years and conversion to cool season grasses of fescue and/or bluegrass may be the best option. Soil Service Garden Center can show you the steps and products needed for this conversion.
(Updated June 2015)