Friday, June 3, 2011

Drought Damage on Zoysiagrass Lawns

Last summer and fall we experienced some widespread drought throughout the state which we documented with turf tips in July, September, and November as well as tips on reestablishment this March (click here for an archive of these tips). Most were uncertain as to what the extent of the damage would be until the turf began to green-up this spring. Many areas came back surprisingly well although many other areas (typically southern slopes, and poor, shallow, compacted or sandy soils) did not do as well. For some warm-season grasses, especially zoysiagrass we are only now able to ascertain the full extent of the damage since these grasses do not fully green-up until late April or May in Indiana. I have fielded a few calls regarding damage to zoysiagrass lawns this spring. Consistent in all these cases the damage seems to occur on unirrigated areas with sandy, shallow, or compacted soils. Most of the damage is limited to small spots or small portions of the lawn.

Although zoysiagrass is a warm-season grass and drought tolerant compared to cool-season grasses, it is still susceptible to drought injury. Meyer (also called Amazoy or Z-52) zoysiagrass is used throughout much of the state because it is the most cold hardy of all the zoysiagrass cultivars, but it only has moderate drought tolerance compared to other zoysiagrasses which can predispose it to drought injury under severe drought conditions as we experienced last summer/fall. Of the turfgrasses grown in Indiana bermudagrass will require less irrigation than ‘Meyer’ zoysiagrass although both are more drought tolerant than cool-season grasses with tall fescue being more drought resistant that Kentucky bluegrass. However, because bermudagrass is not as cold hardy as zoysiagrass we are limited to growing bermudagrass in the southernmost part of the state.

Should drought strike in the future, limit traffic (including mowing) to minimize damage to the turfgrass leaves and crowns and apply irrigation once every 4 weeks with ½ inch of water to keep turf plant crowns hydrated. This amount of water should not green up the turf, but it will increase its long-term survival.

For those with zoysiagrass that was damaged from last summer’s drought and in need of repair, there are three options for reestablishment.

  1. Resodding with Meyer zoysiagrass. Zoysiagrass is available from sod farms in SW Indiana. Homeowners may be able to get sod directly from the grower but some prefer to work through a local landscape companies and you might need to contract out this work.

  2. Seeding zoysiagrass is also an option. Seeding zoysiagrass is only for patient people and will require herbicide applications for best results as weeds easily outcompete zoysiagrass seedlings even though there are few weeds in established zoysiagrass. More information on seeding zoysiagrass is available on our website at this link. NOTE: If a preemergence herbicide application was made this spring then seeding will not be an option for these lawns as the preemergence herbicide will prevent weeds seeds from germinating as well as desirable turfgrass.

  3. Plug zoysiagrass. Using a hand spade or small shovel, cut pieces of sod approximately 3 x 3 inches or larger from healthy portions of your zoysiagrass lawn and plant them on 1 foot centers (using an imaginary grid) in the dead areas. These newly planted plugs will spread and fill in over time (1 year or so) and fill in the bad spots. Be sure to water the new plugs for the first month after planting and don’t forget to fill the holes you made in the rest of your lawn.

Regardless of the method of reestablishment, it is important to first obtain a soil test (soil test instructions, soil testing laboratories) in the area and fix any nutrient or pH problems prior to planting as well as any soil compaction or other limiting soil problems.

Aaron Patton, Assistant Professor/Turfgrass Extension Specialist


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