The Root of it All: Snow mold in the lawn

Now that the snow has melted from my yard I can see some problems. In some areas, the grass is matted down, and in the morning sun it shines and shimmers like it is covered with spider webs. Is this an insect problem? Is there something I should do to correct it, or is my grass dead? Thanks for your help. Lou, Racine.

Spring arrives in a big wet mess in our yards some years, and after the constant snow cover the spring melt reveals lots of unpleasantness. Challenges that might greet you include vole tracks (1-inch wide runways through the grass), yellow spots (do you have a dog?), and matted grass with either sliminess or white patches on the surface.

Shimmery patches of white, spider-web type of growth on your lawn is not an insect issue, nor a spider or mite issue, but a fungal disease called snow mold. There are two types, gray and pink, but what I am seeing mostly is gray snow mold. The bad news is that it is not a very attractive disease, and makes your lawn look a bit slimy. The good news is that it is easily remedied by light raking of the grass but even if you dont rake, the grass will recover.

The snow mold only thrives under the cool, moist protective layer of snow. Once the snow melts and the grass (and the fungal organism) is subjected to the warm, bright sun the fungi will die. The damage, at that point, is done. But the damage is only on the grass blades and should not affect the crown of the plant where new growth emerges. If the patches are raked to loosen the matted grass, sunlight and air will penetrate to the crown more quickly, allowing a faster recovery. If the grass is not raked, new grass will eventually push through the matted grass after a little more time.

It is always a good idea to correctly identify your problem before trying to fix it. In this case, no treatment is needed, which means you save money, time and the environment by not purchasing and applying either an insecticide or a fungicide. Creating a healthy lawn through proper maintenance goes a long way in reducing chemical input and minimizing damage.

The snow apparently was covering up some lawn problems, I have runways of dead grass all through my yard, there are brown stripes running all over. When I can I seed these areas and get my lawn greened up again? Deb, Caledonia.

Voles (also known as meadow mice) can do a lot of damage to the lawn when we have snow cover. They love snow as it gives them protection from hawks, coyotes, dogs, and cats, who all think voles are fabulous food. As voles run through your grass under the snow they feed on any and all available plants and insects. Through that process they make tracks in your lawn. If you follow their trails you will find one of their favorite winter snacks, the tender bark of your small ornamental trees and shrubs.

Voles can kill trees and shrubs if the chewed bark encircles the plant. When spring arrives and buds are breaking, watch those plants at the end of the vole trails to see if they bud out. If not, it could be that damage right at the soil line is severe enough to kill the plant.

Next year consider using hardware cloth (a wire mesh that can be used to cage plants or protect the base of tree trunks) to surround your trees and shrubs worthy of protection. This year consider the meadow mouse habitat and change some of your landscape habits to discourage them from making your landscape their happy home. If you have an evergreen ground cover like pachysandra or creeping juniper, you may have a perfect environment for voles. If the damage is severe, you might want to trap and kill the voles to reduce their population.

The damage to the lawn should repair itself in time if proper healthy lawn care practices are used. If seeding is needed, wait until May when the soil is a bit warmer to seed the damaged areas.

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The Root of it All: Snow mold in the lawn