Preventing spring vole damage starts now

Last spring the voles really did a number on my plants. They ate the bark off trees and the roots off several flowers and bushes. Is there any way to prevent damage next spring? Yes, but there is no single miraculous cure for stopping vole damage. There are various ways to reduce it. Usually, the solutions work best when combined and the time to start vole control for next spring is now.

Voles-not moles-are the culprits. Moles live underground, as do voles. However, moles are smaller than voles and moles eat insects and earthworms. Moles do not live around here. Voles spend more time aboveground than in burrows. They are large mice with short tails; some people call them "field mice." Montana has several species of voles and they all eat plants.

Voles are less likely to be noticed in summer since their favorite food is grass. As long as their grass supply is bountiful, they do little damage in yards and gardens. They are noticeable only when they cut trails of short grass across a lawn. When fall comes, many small mammals hibernate, sleeping through the rigors of winter. Not voles. They are awake all winter and eating steadily.

At this season the plants available to voles are the gardener's treasures. That is why vole damage is so often seen when the snow melts in spring. When a network of crisscrossing lines appears on the ground, looking like a road map, that means trouble. The lines are vole tunnels on the ground and under the snow, made as voles searched for new food sources. With green grass in short supply, the voles turned to bark and roots to stay alive.

The ways to decrease a vole population begin with making your home ground the least attractive place for local voles. There is no way to keep them out but you can make your landscape one which they dislike.

Start by encouraging vole predators-hawks, owls or an outdoor cat.

Cage the trunks of your small trees and those with tender bark in a cylinder of hardware cloth.

Mow a strip around all trees, bushes and flowerbeds any time in August. Voles know that they are low on the food chain. They like to live in tall grass where their paths are hidden, not in short grass, where they are visible to predators. If you have a fenced yard, mow a strip around the outside of the fence. Mown grass serves as a detour sign.

On the same principle, wherever you spread mulch, leave a bare space about two inches wide around tree trunks; never pile mulch around the base of a plant. Voles travel under mulch in the same way that they travel under snow-knowing that they are hidden. If they have to run the gauntlet of being visible before they get to the delicious tree bark, the bark seems less tasty and may not be worth the risk.

This kind of environmental modification must be checked and changed as necessary. Each vole lives only about a year but it is mature enough to start breeding the next generation only two weeks after it is born.

There also are a few ways to kill resident voles. Mouse bait is one, as long as it is hidden where other small mammals and ground-dwelling birds cannot eat it. Leave bait for several days. One meal is not enough to kill a vole; it may only make the vole sick. A recovered vole will stay away from bait in the future.

Traps are most effective if they are placed in vole runways. Put live traps parallel to the runway, snap traps across the runway. Snap traps may be more effective if used in pairs. Bait the traps with peanut butter. Be sure to use traps large enough for a big mouse. The smallest size will trip before the vole's entire head is in the trap. Sometimes traps are more effective if they are in a tunnel made from a cardboard box.

Sometimes voles are discouraged by powdered coyote or fox urine, sometimes not.

Being well-prepared for voles now is the best guarantee of less damage next spring.

Hackett welcomes reader questions related to gardening, pest management, plants & soils. Submit questions to mhackett@centric.net, call 406-961-4614 or mail questions to 1384 Meridian Road, Victor, MT 59875.