Moles don’t usually eat plant matter, focusing instead on insects. However, rodents such as mice and voles use their tunnels like a subway, and they do eat roots and bulbs. As you plant, mix products made from crushed oyster shells into the soil surrounding the bulb. This makes for tough digging for the rodents, and they might be induced to look elsewhere for a meal. Some gardeners resort to planting bulbs in little cages made of hardware cloth (wire mesh) to keep critters from munching on the bulbs.