By Adam Thoms, Iowa State University
This past winter was a hard one on lawns in Iowa. Many yards in the state were not looking as good as they normally do by April and May. Yards had dead spots and brown leaves much longer into the spring than normally expected. This past winter was harder than most years because for much of the late fall and winter, we lacked snow cover. Snow cover typically insulates the lawn and protects it from the temperature swings that the turfgrass saw this past winter.
While Kentucky bluegrass is very cold tolerant (with its range going up into Alaska and Russia), most Iowa lawns are a mixture of turfgrass species including perennial ryegrass and tall fescue which are not as cold tolerant. Additionally, Kentucky bluegrass seedlings are not as cold tolerant as established plants and if you seeded in the fall, you might have seen some death in those areas. Yards that did not green up or took a really long time to green up in the spring saw winter damage.
A dry spring can slow the yard from breaking dormancy and cause stress, especially under trees where water is already at a premium (Fig. 1). So, what can be done if you suspect your yard has winter damage in the spring? You can water to see if it will help break dormancy. Applying 1” of water over the course of a week and seeing if the green cover improves is a simple way to look and see if your lawn is struggling due to a dry spring, or if it is winter injury. If the yard does not start to green up a couple of days after adding water, your yard may have winter damage. You can reseed spots that are still not turning green, but this is not an option if you applied a preemergence herbicide. If you have applied a preemergence herbicide then you will need to lay sod to those areas or wait until the fall to seed. We have not seen widespread winter injury in several years, so this is not a very common issue in Iowa, which made for a very memorable spring. Timely summer rains and favorable temperatures allowed for recovery in many of these yards. Hopefully the upcoming winter will bring some snow cover to protect the lawns in the Midwest. Researchers from the WinterTurf project are working to develop new turfgrass cultivars that will be able to survive and thrive both typical winters and those rare, but damaging, stressful winters like we experienced in Iowa.