CO-Horts Blog

Monday, March 14, 2016

The Snow has Melted...

Tony Koski, Extension turf specialist

Gray snow mold after the last of the snow has melted
…and people are REALLY worried about their lawns! Some are seeing vole injury. Many are seeing snow mold. And more than a few are plagued by both. While these two lawn problems may seem unrelated, they have a common cause: long-term snow cover.

You can see the "mold" (mycelium) if you look closely!
If you rough up the matted
grass you will find living
grass shoots underneath
Regarding snow mold, the most common places it is being seen is where snow accumulated on the north sides of buildings and fences, or where shoveling and plowing piled it on turf near sidewalks and driveways. As we speculated in an earlier blog that it might happen, gray snow mold has made an appearance in many Colorado lawns this year. While it looks bad, gray snow mold is rarely fatal in home lawns (although tall fescue can be killed by severe gray snow mold). Raking the matted grass to hasten its drying is really the main thing that needs to be done to get snow mold-affected grass growing again. However, if you can’t remember the last time you fertilized your lawn, a spring application of nitrogen (at least half should be slowly available nitrogen…you can find this on the label) can also help speed green-up and recovery. There is absolutely NO reason to apply a fungicide to lawns afflicted with snow mold – no matter what your lawn care company or other expert might tell you.

Vole trails adjacent to a shrub
bed that is covered with
weed barrier and mulch - an
ideal vole hangout!
Vole activity on lawns has also favored by long-lasting snow cover – especially if that snow was adjacent to an un-mowed greenbelt/native grass/natural area, or a mulched shrub bed (especially with junipers). Voles especially like living under the landscape fabric (aka “weed barrier”) that is often installed under mulch and gravel in landscape beds. Voles will venture out into snow-covered lawns from the shelter of tall grass and juniper to feed on the lawn – creating trails under the snow. The longer the snow lasts, the more trails they make and the more severely they can damage the lawn. As with snow mold injury, the turf will usually recover from vole feeding. However, where vole numbers are high and snow cover is especially long-lasting, turf may be killed by the persistent vole feeding – sometimes requiring reseeding or spot sodding.
As with snow mold injury, this
grass is already growing back
in a vole trail.

When the snow melts, the snow mold disease ceases to be a problem (ultra violet light from the sun pretty much stops its growth) and the voles are reluctant to feed on the lawns without the shelter provided by snow cover. In most cases, a little TLC will get your lawn back to where it was before the voles and snow mold visited it this winter.

Read more about voles in your lawn here and here.
Voles love living in beds covered with landscape
fabric (aka "weed barrier") and mulch

1 comment:

  1. Thanks, Tony
    My spring turf problem is dog urine spots. I read CMG GardenNotes #553 and can be patient to see whether the turf is really dead, but I've used compost tea in the past with success. Was that a placebo effect on grass that would have recovered anyway, or does a mild dose of N and microbes help?