The groundhog, also known as the woodchuck or Marmota monax, is a large, herbivorous rodent belonging to the squirrel family. They are powerful excavators, spending most of their time constructing and residing within complex subterranean tunnel systems. While their presence in the ecosystem is natural, their habits frequently bring them into conflict with homeowners and gardeners. Their feeding and extensive burrowing activity make them one of the most common and destructive garden pests. They cause significant damage to landscaping, crops, and even the structural integrity of buildings.
Specific Ways Groundhogs Damage Property
Groundhog damage manifests in two primary ways: through extensive tunneling and through destructive feeding habits. A single groundhog burrow can be quite large, with the main tunnel extending anywhere from 15 to 30 feet in length, sometimes reaching up to 66 feet, and descending as deep as six feet below the surface. This excavation results in large mounds of soil near the main entrance, creating an immediate tripping hazard for people and pets.
The hidden network of tunnels creates unstable ground. When burrows are dug beneath concrete slabs, patios, or walkways, the removed soil causes voids that can result in the cracking, sinking, or uneven settling of these structures. Groundhogs often tunnel directly underneath sheds, porches, decks, and even home foundations, compromising the structural stability of these features by eroding the supporting soil. Over time, these voids can also redirect water flow, potentially leading to drainage issues, increased basement moisture, and even foundation failure.
Groundhogs also inflict considerable damage to vegetation. They consume a wide variety of plants, with a strong preference for legumes like clover and alfalfa, as well as many common vegetables, including peas, beans, and lettuce. They are voracious eaters, capable of consuming up to a pound of vegetation daily. Beyond eating garden crops, they may also gnaw on the bark of young trees, a process called girdling, and damage ornamental plants and flowers.
Confirming Groundhog Activity
Identifying groundhog activity requires looking for specific signs that differentiate their work from that of other burrowing animals like moles or skunks. The primary indicator is the main burrow entrance, which is typically a large, round hole measuring between 8 and 12 inches in diameter. This main opening is almost always accompanied by a large, fan-shaped mound of excavated dirt immediately outside, often consisting of displaced soil and rocks.
A groundhog burrow system will also feature one to four secondary entrances that are often hidden or lack the obvious dirt mound, as the groundhog excavates these escape routes from the inside. Another sign is the presence of clear pathways, or “runs,” worn down through the grass between the burrow entrance and nearby feeding areas. Groundhogs are diurnal, meaning they are active during the day, particularly in the early morning and late afternoon, which increases the likelihood of a homeowner catching a glimpse of the pest.
Exclusion and Deterrence Strategies
Addressing a groundhog problem requires a focus on physical exclusion and habitat modification to prevent both feeding and future burrowing. The most effective long-term solution for protecting a garden or structure is the installation of a specialized fence, as groundhogs are adept at both climbing and digging. This barrier must be at least three feet high, constructed of heavy-duty wire mesh or hardware cloth, and should be angled outward to prevent climbing.
The fence must extend underground in an “L-shaped footer” to prevent the animals from burrowing beneath it. The bottom of the wire mesh must be buried at least 10 to 12 inches deep, with an additional 6 to 12 inches of mesh bent outward at a 90-degree angle away from the protected area. When securing a structure like a shed or deck, this L-shaped wire exclusion should be attached securely to the base and buried, making it impossible for the groundhog to dig past the horizontal barrier.
Making the yard less appealing is an additional step in deterrence. This includes removing potential shelter spots, such as brush piles, overgrown vegetation, and wood stacks, which groundhogs use for cover. Homeowners can also try non-toxic deterrents, such as applying strong-scented repellents like garlic or fox urine near burrow entrances. To reduce the food source attraction, ripe produce should be harvested promptly, and weeds should be managed. If the groundhog has already established a burrow under a structure, professional intervention, such as humane trapping and relocation, is often necessary before permanent exclusion can be completed.