Homeowners often suspect the mole when daffodil bulbs or other garden plants are damaged, as visible mounds and raised tunnels indicate activity beneath the soil surface. While garden disruption is frustrating, correctly identifying the responsible pest is the first step toward effective mitigation. Understanding the distinct habits and dietary needs of burrowing creatures reveals that the animal creating the tunnels is rarely the one consuming the bulbs.
The Primary Diet of Moles
Moles are insectivores, meaning their diet consists almost entirely of meat in the form of invertebrates. Earthworms make up the majority of their sustenance; they often consume a quantity nearly equal to their own body weight daily to sustain their high metabolism. Moles also actively hunt and consume grubs, beetle larvae, spiders, and other small soil-dwelling insects.
The extensive tunnel systems moles create are hunting grounds designed to trap prey, not to access plant roots. While their tunneling activity can indirectly damage plants by disturbing root systems, the mole has no biological interest in plant matter. A mole’s specialized sharp claws and pointed snout are adapted for digging and catching worms, not for gnawing through dense bulbs.
Identifying the True Bulb Eaters
The actual culprits for consuming daffodil bulbs are typically rodents, primarily voles, and sometimes gophers or squirrels. Voles are herbivores with a diet of roots, bark, seeds, and various plant parts, making them the most likely underground consumer. Unlike the volcano-shaped mounds created by moles, voles create small, neat entry holes near plants or shallow, unraised runways just beneath the soil surface.
Daffodil bulbs offer a natural defense against most pests because they contain the toxic alkaloid lycorine, with the highest concentration found in the bulb itself. This compound causes gastrointestinal distress, which is why animals like deer and rabbits generally avoid eating them. However, voles are often undeterred by this toxicity and will still feed on the bulbs, especially when other food sources are scarce.
Physical evidence of vole damage includes distinct, small tooth marks on the bulb surface or the bulb being entirely hollowed out, leaving only a chewed outer shell. These rodents often use the existing, easy-to-navigate tunnels created by moles to move through the underground environment and access their preferred plant-based food sources. Identifying the difference between the mole’s disruptive tunneling and the vole’s specific feeding marks is key to addressing the correct pest.
Protecting Daffodil Bulbs from Garden Pests
Since voles pose the primary threat to the bulbs, non-lethal physical barriers offer the most reliable form of protection. When planting, bulbs can be placed inside individual wire cages or baskets constructed from half-inch gauge hardware cloth. This fine-mesh material prevents the voles from burrowing to the bulb while still allowing the roots and shoots to grow unhindered through the openings.
Another effective strategy involves incorporating sharp, coarse materials into the soil surrounding the bulbs. Adding a layer of crushed granite, oyster shells, or sharp gravel to the planting hole and covering the bulb with it discourages voles from chewing or digging through the area. These abrasive materials make tunneling and foraging difficult, prompting the rodents to seek easier feeding locations.
Applying commercial repellents based on castor oil can also make the protected area unappealing to voles. The castor oil creates an unpleasant taste and odor in the soil, which is thought to disrupt the vole’s sense of smell, guiding them elsewhere to forage. These liquid or granular repellents must be applied directly to the soil and reapplied periodically, especially after heavy rain, to maintain a consistent barrier against the pests.