Voles are small, mouse-like rodents that often become destructive garden pests, yet they are frequently confused with the insectivorous mole or the common house mouse. These herbivores are active year-round and can rapidly damage lawns and plantings, often remaining unseen until the destruction is extensive. A common gardening question is whether planting marigolds, known for their strong scent, can protect a garden from these burrowing creatures, which helps clarify effective management strategies.
Vole Reaction to Marigolds
The belief that marigolds act as a natural vole deterrent is a misconception, as these plants do not repel rodents. While marigolds (Tagetes spp.) ward off certain pests, such as root-knot nematodes and some insects, they do not produce a chemical compound that discourages voles. Voles are driven primarily by hunger and will typically bypass marigolds, or consume them during periods of food scarcity.
The strong odor of marigolds may discourage moles, which rely heavily on scent to locate insect prey, but voles are rodents whose foraging behavior is not deterred by the plant’s aroma. Relying on marigolds as a protective border for vulnerable plants will likely lead to disappointment.
Preferred Vole Food Sources
Voles are herbivores focused heavily on the underground portions of plants, including roots, tubers, and bulbs. Their primary food sources include grasses and herbaceous plants, but they readily consume large, starchy bulbs like tulips, lilies, and crocuses. They become especially problematic in the winter months when their usual surface vegetation is scarce or hidden beneath snow cover.
During this colder season, voles shift their focus to the bark of young trees and shrubs, often gnawing away the cambium layer at the base of the trunk. This girdling damage can completely encircle the plant, effectively cutting off the flow of nutrients and often leading to the death of the tree or shrub. Subterranean feeding on roots can also cause trees to appear sickly or wilted before the root destruction is noticed.
Identifying Vole Damage
Confirming vole activity requires observing specific signs that distinguish their presence from other burrowing pests. The most characteristic sign is the presence of shallow, above-ground runways created in the grass or mulch, typically one to two inches wide. These pathways are formed as voles clip the grass blades and compact the soil from repeated travel between feeding areas and burrow openings.
Burrow entrances are small, clean, and round holes, usually an inch or two in diameter, often located directly within the surface runways. On woody plants, look for distinct, irregular gnaw marks approximately 1/16 to 1/8-inch wide, usually found low to the ground or just below the soil line. If a plant appears suddenly wilted and can be easily lifted from the soil, it indicates the roots have been severed or consumed.
Non-Lethal Vole Management
Effective, non-lethal management of voles centers on habitat modification and physical exclusion to make the environment less hospitable. Begin by eliminating heavy ground cover, dense weeds, and thick layers of mulch, which provide voles with food and protected travel routes. Regularly mowing the lawn to keep grass short also reduces their ability to move unseen by predators.
Protecting susceptible plants involves the use of physical barriers, which is a reliable method. For young trees and shrubs, install cylinders made of 1/4-inch hardware cloth around the trunks, ensuring the mesh extends at least six inches below the soil line to prevent burrowing underneath. When planting valuable bulbs, placing a layer of coarse gravel in the planting hole can act as a deterrent, as voles dislike digging through the sharp material. Commercial repellents containing castor oil or capsaicin can also be applied to plants and bulbs to make them taste unpleasant, although reapplication is necessary after rain.