Gardeners often find their beautiful spring bulbs mysteriously vanishing or dug up. Many people suspect squirrels or moles, but the real culprit is often the vole, a small, unassuming rodent resembling a chunky field mouse. Voles are distinguished by their compact bodies, short legs, and a tail noticeably shorter than their body. This article confirms the vole’s appetite for tulips and details strategies necessary to protect your garden.
The Direct Answer: Vole Diet and Tulip Preference
Yes, voles actively consume tulip bulbs, finding them a highly appealing and concentrated food source. Voles are herbivores, and buried bulbs become a crucial part of their survival strategy during winter. Tulip bulbs are rich in starches and lack the bitter chemical compounds that deter rodents from eating other types of bulbs. This lack of natural defense makes tulips a preferred meal. In contrast, bulbs like daffodils and snowdrops contain toxic alkaloids, such as lycorine, which make them poisonous to voles.
Identifying the Culprit: Vole vs. Other Garden Pests
Identifying the pest is the first step toward effective control, as vole damage is distinct from that of other garden invaders. Voles create shallow, exposed surface runways, which are narrow, well-worn paths through the grass or under mulch. Their burrow entrances are small, clean, open holes, generally about an inch and a half in diameter, and they do not feature large soil mounds.
Moles, which are insectivores, do not eat bulbs; their tunneling causes indirect damage by severing roots. Mole activity is identifiable by raised, volcano-shaped mounds of soil and visible ridges in the lawn, not the clipped trails left by voles. When a vole eats a bulb, it leaves behind a clean-cut, hollowed-out shell. Squirrels tend to dig from above, often leaving the bulb unearthed.
Immediate Protection Strategies for Newly Planted Bulbs
The most effective immediate defense is creating a physical barrier around vulnerable bulbs at the time of planting. Individual bulbs or entire planting areas can be encased in baskets constructed from quarter-inch hardware cloth. This galvanized steel mesh must fully enclose the bulbs, extending at least six inches deep to prevent voles from tunneling in from the side or below.
Another protective measure is to incorporate sharp, gritty materials directly into the planting hole. Adding crushed oyster shells, poultry grit, or coarse gravel around the tulip bulbs deters voles, which dislike burrowing through abrasive material. Non-toxic repellents, such as liquid or granular products containing castor oil or capsaicin, can also be used as a bulb dip or soil drench to make the immediate area unappealing.
Long-Term Vole Population Management
Reducing the overall vole population requires modifying the garden habitat to make it less hospitable. Voles rely on dense cover to hide from predators, so eliminating heavy mulch layers and keeping grass cut short removes their protective canopy. Creating a buffer zone of short grass or bare ground, at least 10 to 15 feet wide, around vulnerable plantings will discourage voles from venturing into the open.
Trapping is a highly effective long-term control method for established populations. Standard snap-traps, baited with peanut butter or apple slices, should be placed directly inside or perpendicular to the active surface runways. Traps must be covered with a box or tunnel to protect pets and children, while mimicking the vole’s safe, enclosed environment. Encouraging natural predators, such as by installing owl or hawk perches, also helps maintain a balanced ecosystem.