The sudden disappearance or damage to newly planted flower bulbs often leads gardeners to suspect the common mole. These subterranean mammals are frequently blamed for the vacant spots where colorful spring blooms were expected. While mole activity signals disruption, the assumption that they are consuming the bulbs directly is a widespread misconception. Understanding the true habits of these animals and identifying the actual pests responsible is the first step toward protecting your investment and ensuring a vibrant spring display.
Understanding the Mole’s Diet
Moles are insectivores, meaning they do not consume plant material such as flower bulbs or roots. Their diet is composed of soft-bodied invertebrates found in the soil, including earthworms, grubs, centipedes, and insect larvae. A single mole must eat a volume of food nearly equal to its body weight each day to maintain its tunneling activity.
The damage attributed to moles is an indirect result of their constant foraging and tunneling. When a mole moves through the soil, their tunnels inadvertently sever or displace the root systems of plants and bulbs. This disturbance causes plants to become stressed, leading to wilting, stunted growth, or the failure of a bulb to emerge. The tunnels also create underground pathways that other animals use to access the bulbs.
Identifying the Real Bulb Eaters
The actual culprits responsible for consuming flower bulbs are rodents, specifically voles, squirrels, and mice. Voles are small, mouse-like rodents that are dedicated herbivores with an appetite for plant roots, tubers, and bulbs. Unlike moles, voles live both above and below ground, creating shallow tunnels and surface runways roughly two inches wide through grass or mulch.
Voles cause extensive damage by burrowing directly to the bulb from below and consuming the entire structure. The sign of vole feeding is a clean, gnawed edge on the remaining bulb tissue, or the complete absence of the bulb. Squirrels and chipmunks are frequent offenders, but their damage is usually visible on the soil surface. They tend to dig up and carry away newly planted bulbs. These rodents are attracted to popular varieties like tulips and crocus, often locating them by the scent of the freshly disturbed soil.
Protecting Your Flower Bulbs
Protecting bulbs from rodents requires focusing on physical barriers and natural deterrents. The most effective method is to create an underground “cage” for the bulbs using hardware cloth or wire mesh with a half-inch grid opening. This material is stiff enough to prevent rodents from chewing through it and allows roots and shoots to pass while fully enclosing the bulb.
Another deterrent involves making the planting environment undesirable for pests. Planting bulbs with sharp, gritty materials, such as crushed oyster shells or coarse gravel, can discourage voles and mice from digging near the bulbs. Applying commercial repellents based on castor oil or planting with strong-smelling substances like granulated garlic or chili pepper can mask the appealing scent of the bulbs. Gardeners can also select varieties that rodents naturally avoid, which contain compounds unpalatable to voles and squirrels:
Daffodils
Alliums
Fritillaria
Hyacinths