The sudden wilting of a healthy plant or the disappearance of a favorite tulip bulb can be a frustrating mystery for any gardener. When the damage originates below the soil line, the cause is often the vole, a small, unassuming rodent sometimes called a meadow mouse or field mouse. Voles are herbivores that cause significant damage by consuming plant roots, bulbs, and the bark of woody plants. Operating mostly unseen in shallow underground tunnels, their feeding habits can lead to the complete collapse of a plant, leaving little more than a hollowed-out root crown. Understanding the specific signs of their activity and implementing physical barriers are the first steps toward protecting your landscape.
Confirmation: Identifying Vole Damage
Identifying the culprit is the first step, as vole damage is often confused with that caused by moles or gophers. Voles create a distinct pattern of surface runways, which are narrow trails, typically one to two inches wide, visible through matted grass or under mulch. These runways are formed as the voles clip vegetation and run the same path repeatedly while seeking cover. Small, circular burrow entrances, often dime-sized to one and a half inches across, connect the surface runways to their shallow tunnel system.
Unlike gophers, voles do not leave large, crescent-shaped mounds of dirt. Unlike moles, who are carnivores, voles are vegetarian and cause direct damage to plant tissue. The most telling sign is the evidence of gnawing on the plant itself, especially near the soil line. Voles leave small, irregular gnaw marks on stems and bark, usually about one-sixteenth to one-eighth of an inch wide. If a wilting plant separates easily from the ground when pulled, the roots have likely been cleanly severed just below the surface, a hallmark of vole feeding.
The Vole Menu: Plants Most at Risk
Voles are opportunistic feeders, but they exhibit a strong preference for plant parts with high starch or sugar content. Many popular spring-flowering bulbs are prime targets, with tulips, crocuses, and lilies frequently being completely consumed underground. Gardeners often discover hollowed-out bulbs or entire plants pulled into the entry holes of the burrows.
Root vegetables are highly susceptible to damage, as voles tunnel directly to the food source and feed on it below ground. Crops such as:
- Carrots
- Potatoes
- Sweet potatoes
- Beets
can be partially eaten or entirely destroyed before harvest. Additionally, voles chew the bark of young trees and shrubs, a behavior known as girdling, especially during the winter when snow cover provides protection. Girdling removes the tree’s phloem layer, which starves the root system and can eventually kill the plant.
Physical Barriers and Habitat Modification
Protecting high-value plants requires physical barriers, which are the most effective non-chemical solution. For planting individual bulbs or small root crowns, creating root cages out of quarter-inch hardware cloth offers a durable defense. This fine mesh size excludes voles while still allowing the plant’s roots to grow through over time.
When planting young trees or shrubs, a cylindrical guard made from the same quarter-inch wire mesh should be installed around the trunk. This barrier must extend several inches below the soil line to prevent tunneling and several inches above the expected snow line, as voles often feed under the cover of snow. The mesh should not press tightly against the trunk, allowing for future growth.
Modifying the surrounding habitat can also make an area less appealing to voles, who rely on dense cover for safety. Regularly mowing the lawn and removing excessive weeds eliminates the tall vegetation that provides protective surface runways. Clearing away debris, such as piles of leaves, dense groundcover, or deep mulch layers near planting beds, removes their preferred nesting and travel areas.
Voles dislike exposing themselves in open areas, so maintaining a clear, four-foot buffer zone around vulnerable plants can deter their activity. As a further deterrent in high-risk areas, coarse materials can be mixed into the soil during planting. Surrounding bulbs with sharp gravel or coarse sand, for instance, can discourage voles from tunneling and feeding directly on the plant tissue.