By: Billy Skaggs, Hall County Extension Agent

 

Over the last several years, I have been flooded with questions and concerns from area residents who have zoysiagrass lawns. Most often, the homeowner describes the lawn as “having bare spots” and “slow to green-up.”

 

In talking with UGA Extension Turf Specialists Clint Waltz and Gil Landry over the years, I’ve come to the conclusion that many of the problems are associated with how the lawn is cared for. The following is a list of possible causes and solutions compiled from my experiences dealing with zoysiagrass problems and working with turf experts.

 

1)      Mowing height appears to be the most common problem associated with spring transition. Zoysiagrasses in general and the denser the growth type (i.e. ‘Emerald’), the more common scalping problems occur. Zoysiagrasses do not tolerate scalping like bermudagrass. When zoysiagrass is cut low enough that the black mold under the leaf canopy is visible, it will be set back. This is generally below the node of the growing leaves. This can occur at any mowing height, from as low as 0.5 to over 3 inches. Regardless of the normal mowing height, taking the grass down below the node will set it back. Generally, the higher the mowing height, the more this is a problem. Ideally zoysiagrass should be cut at 0.5 to 1.5 inches. Mowing frequency is just as important. Take care not to remove any more than 1/3 of the height at any one mowing.

 

2)      Fertility: 2 pounds of N per 1000 square feet per year is all that is needed by zoysiagrasses. Excessive nitrogen. Although higher N rates produce greener grass, it also reduces the slow-growth characteristics of the grass, increases mowing and irrigation requirements, often increases

bermudagrass invasion, and will increase thatch and associated problems.

 

3)      Thatch: as lawns become older thatch becomes more problematic particularly if the turf has been mowed above 2 inches. The effects of increased thatch is slow spring transition and a greater likelihood of disease incidence

 

4)      Water: either too much or a lack of and even a combination of the two can cause problems for grasses, especially zoysiagrass.

 

5)      Disease: the most common disease problem during green-up of zoysiagrass is Rhizoctonia large patch which has similar symptoms to Brown Patch. This disease is most active when night temperatures are between 50 and 60 degrees. So normally it first hits in the fall and becomes active again in the spring under appropriate temperatures. This disease is controlled by fall and spring applications of a labeled fungicide.

 

6)      Cool temperatures: zoysiagrasses are typically slower to green-up particularly during cool springs. Also, ‘Emerald’ zoysiagrass growing north of Atlanta is prone to being killed by low temperatures in shaded sites that don't get much winter sun.

 

For more information on this and other turf problems, visit the UGA Turfgrass Homepage at www.georgiaturf.com.