Burrowing animals can quickly transform a garden into a network of tunnels, causing significant damage beneath the soil surface. These subterranean residents often compromise the integrity of lawns, sever plant root systems, and may even undermine paved walkways or foundation structures. Effective management requires a multi-faceted approach, moving beyond simple fixes to implement long-term strategies. This guide outlines solutions, from accurate identification to physical exclusion and direct control, offering a clear path to protecting your outdoor spaces.
Identifying the Burrowing Culprit
The first step is accurately identifying the species responsible for the damage, as control methods are highly species-specific. Moles create characteristic volcano-shaped mounds that are often circular and composed of finely sifted soil pushed up from below. They are insectivores, using extensive tunnel systems and raised surface runways to hunt earthworms and grubs, not to consume plant roots.
Pocket gophers are rodents that feed primarily on roots, tubers, and bulbs. Their mounds are typically fan-shaped or crescent-shaped, and the central entrance hole is usually distinctly plugged with soil. This plugged hole is a key differentiator from molehills, which often show no visible opening.
Groundhogs, also known as woodchucks, create much larger, more obvious open holes, sometimes 10 to 12 inches in diameter, often near structures or dense cover. Unlike moles and gophers, groundhogs are herbivores that feed heavily on above-ground vegetation. Their large burrows can extend up to 65 feet in length. Identifying the pest based on these distinct signs dictates which management technique will be most appropriate.
Exclusion: Building Physical Barriers
Physical exclusion is the most reliable long-term strategy for preventing access to protected garden areas. Installing an underground barrier requires digging a trench around the perimeter, using heavy-gauge, galvanized hardware cloth with openings no larger than one-half inch. Chicken wire is not recommended because gophers can chew through it.
The wire barrier should be buried to a minimum depth of 18 inches, though 24 inches offers greater security, to prevent animals from digging underneath the material. A crucial component is the “L-footer,” which involves bending the bottom portion of the wire mesh outward at a 90-degree angle. This horizontal flange acts as a deterrent, frustrating the upward digging efforts of gophers and other burrowers.
For protecting individual, high-value plantings, specialized wire cages or “gopher baskets” can be constructed from the same hardware cloth to enclose the root ball upon transplanting. When constructing raised garden beds, securing a layer of half-inch wire mesh across the entire bottom surface before filling it provides an effective, permanent horizontal barrier. This mesh is strong enough to keep gophers out while still allowing plant roots to penetrate the openings.
Deterrence: Using Repellents and Habitat Modification
Deterrence methods aim to make the garden undesirable through sensory disruption or by eliminating attractants. Repellents often target the animal’s sense of smell or taste, requiring consistent application to maintain effectiveness. Castor oil-based products are a common repellent for moles; the substance is applied to the soil and makes the mole’s primary food sources, like earthworms and grubs, unpalatable.
These products, whether granular or liquid, must be watered thoroughly into the soil to penetrate the subsurface tunnels. Since repellents are subject to weathering and leaching, frequent reapplication is necessary, often after heavy rain or irrigation, to sustain a protective boundary. The effectiveness of sonic or vibratory devices is mixed, as animals may be temporarily displaced but quickly habituate to the disturbance.
A systematic approach involves modifying the habitat by eliminating or controlling the animal’s food source. For moles, this means reducing the population of lawn grubs and earthworms through biological control or selective watering, making the area less appealing for foraging. Eliminating dense brush piles and thick groundcover also helps, as these provide crucial shelter for species like voles and groundhogs, encouraging them to seek refuge elsewhere.
Direct Control: Trapping and Humane Removal
When prevention and deterrence methods prove insufficient, direct control through trapping becomes the option for removing established pests. Trapping involves the strategic placement of lethal or non-lethal devices directly into the animal’s active tunnel systems or at the burrow entrance. Specialized lethal traps, such as the scissor or choker loop types, are designed to be triggered by the mole or gopher as it attempts to clear the obstructed tunnel.
For larger animals like groundhogs, live cage traps are used at the burrow opening, requiring careful handling of the captured animal. Before utilizing any trapping method, consult local and state wildlife laws, as restrictions exist regarding the type of trap and the legal relocation of captured wildlife. Relocation is often illegal or requires a specific permit because it can stress the animal, spread disease, or transfer the problem to a new location where the animal struggles to survive.
Chemical methods, including fumigants and poisons, are available but carry significant risks, particularly the danger of secondary poisoning to pets, children, and non-target species. These options are complex and are best left to licensed pest control professionals who understand the safety protocols and legal requirements. Trapping, when performed correctly and legally, offers a precise method for dealing with persistent burrowing issues.