Voles are small rodents that inflict significant damage upon gardens and landscapes. These herbivores primarily feed on vegetation. Their most destructive habits include gnawing on plant roots, consuming flower bulbs, and girdling the bark of young trees and shrubs. Girdling, where a complete ring of bark is removed, interrupts the flow of nutrients and water, often leading to the plant’s death.
Identifying the Garden Intruder
Voles leave distinct evidence of their presence. The most common sign is a network of shallow, well-defined surface runways, roughly one to two inches wide, created by clipping grass and pushing aside leaf litter. These pathways are used for foraging and often lead to small, inconspicuous burrow entrances about an inch in diameter. Unlike moles, voles do not leave volcano-shaped soil mounds.
Differentiating voles from other common garden pests is important. Moles are insectivores that tunnel for grubs, leaving raised ridges and large, conical soil mounds. Voles are vegetarians that rarely heave the soil, instead creating narrow, above-ground trails. Voles also differ from house mice, which have long tails and seek shelter indoors; voles have stockier bodies, shorter tails, and concentrate their activity in dense ground cover.
Building Physical Barriers
Physical exclusion is effective for protecting high-value plants like trees, shrubs, and perennial bulbs. Barriers prevent voles from reaching vulnerable root systems and bark. Use galvanized hardware cloth with a mesh size of one-quarter inch or less, as voles can squeeze through larger openings like standard chicken wire.
To protect bulbs and root vegetables, construct wire cages or baskets to surround the root ball before planting. These cages must completely enclose the root zone and be buried deep enough to deter subterranean burrowing. Bury the mesh at least six to twelve inches deep, often with the edges bent outward in an “L” shape to discourage voles from digging underneath.
For young trees and shrubs, barriers shield the lower trunk from girdling damage, which is common when voles forage under snow cover. Create a cylinder of hardware cloth around the trunk that extends twenty-four to thirty-six inches above the ground and is buried a few inches into the soil. The mesh must be loose enough for future trunk growth but secure enough to prevent voles from climbing between the guard and the bark.
Changing the Environment and Using Repellents
Modifying the garden environment to reduce protective cover and food sources can make the area less appealing to voles. Voles prefer to travel under the safety of dense vegetation and debris, so eliminating this habitat is an effective cultural practice. This includes keeping lawns mowed to a low height and clearing away wood piles, garden debris, and thick weeds from around vulnerable planting beds.
Mulch management is important, as voles tunnel and nest in deep layers of organic material. Reducing the depth of mulch around trees and plants to less than three inches removes this insulating cover and exposes the rodents to predators. For particularly susceptible areas, replacing organic mulch with a three-foot ring of crushed rock or coarse gravel around the base of plants can deter voles, who dislike traveling through such exposed material.
Commercial repellents work by creating an unpleasant taste or smell, and the most common active ingredients are capsaicin and castor oil. Capsaicin-based products are applied directly to the bark of trees and shrubs to discourage gnawing through taste aversion. Castor oil products are typically applied to the soil and are thought to irritate the voles’ digestive system or taint their food source, encouraging them to relocate. While repellents can provide short-term protection, their effectiveness is highly variable, especially during wet weather which necessitates frequent reapplication.
Direct Population Control
When prevention methods are not enough, direct reduction of the existing population becomes necessary, with trapping being the most targeted approach for the home gardener. Standard mouse-sized snap traps are highly effective and should be placed directly into active vole runways. Voles are hesitant to deviate from their established paths, so the traps do not always require baiting, though a small smear of peanut butter or a slice of apple can increase success.
For the best results, traps should be set perpendicular to the runway so that the vole must cross the trigger plate as it moves along its path. To protect non-target animals and pets, and to encourage the secretive voles to approach the trap, cover the set traps with an inverted can, shingle, or small box. Due to the high reproductive rate of voles, you should deploy multiple traps simultaneously in areas of high activity.
Rodenticides are available for vole control, but their use requires extreme caution due to the risks they pose to children, pets, and beneficial wildlife. If you choose to use baits, they must be placed inside tamper-resistant bait stations that are secured to the ground and positioned directly in the active runways. Using rodenticides without these safety precautions significantly increases the risk of accidental primary poisoning or secondary poisoning of predators that consume a poisoned vole.