Meadow vole damage is almost exclusively above the ground on the first six inches of the main stem. A stiff wire mesh, hardware cloth is available at home centers and hardware stores. First, use a shovel to cut the ground around the plant just enough to insert the wire cylinder. Then form the hardware cloth into a cylinder. The bottom edge of the cylinder should be buried at least six inches below the ground.
Toxicants are perhaps the best way to control voles.
When using toxic baits, care should be used to ensure the safety of children and pets as well as non-target animals. Usually baiting every other day for five days will be most effective. Broadcast the bait evenly over the entire area that is infested. The bait must be available until the vole population is controlled. Buffer strips of closely mowed grass 15 feet wide around gardens and landscapes will help discourage these rodents from crossing over from ditches and other unkempt areas.