Groundhogs are overwhelmingly herbivorous, with a diet built around green vegetation, clover, alfalfa, dandelions, and a wide variety of garden crops. Their diet is dominated by plants, though they do eat a small proportion of insects as well.1ScienceDirect. Dental Pathology of the Hoary Marmot (Marmota caligata), Groundhog (Marmota monax) and Alaska Marmot (Marmota broweri) What makes their eating habits especially interesting is how dramatically they shift across seasons, driven by the biological demands of hibernation and fat storage.
The Greens That Make Up Most of Their Diet
If you watch a groundhog foraging in a field or along a woodland edge, it will almost always be eating green, leafy plant material. Wild plants form the backbone of their diet. Clover, alfalfa, dandelion greens, plantain, chickweed, and various grasses are staples they return to repeatedly. They also browse on the leaves and flowers of wild mustard, goldenrod, sorrel, and blackberry canes. In general, they gravitate toward tender, succulent vegetation rather than tough, woody material.
Groundhogs have a particular fondness for legumes. Clover and alfalfa are probably the two wild plants they eat most consistently across their range. Both are nitrogen-rich, relatively easy to digest, and grow abundantly in the open meadow and field-edge habitats where groundhogs prefer to set up their burrows. If you see a groundhog burrow near an alfalfa field, the association is not a coincidence.
They are also enthusiastic foragers of garden vegetables, which is the main reason they become a headache for gardeners. Lettuce, peas, beans, squash, broccoli, and other brassicas are all targets. They eat the leaves, stems, and sometimes the fruits of these plants. Groundhogs seem especially drawn to young, tender growth, so a newly sprouted garden is more vulnerable than a mature one with toughened stems.
Fruits, Seeds, and the Occasional Bark
While leafy greens dominate, groundhogs eat fruits when they can get them. Berries are a favorite, including wild strawberries, blackberries, and raspberries. They will also eat fallen apples, cherries, and other tree fruits. These sweeter foods become more attractive in late summer and early fall, when groundhogs are actively trying to put on fat before hibernation. The sugar and calorie content of fruit makes it a useful supplement to their otherwise leafy diet.
Bark, twigs, and buds get some attention in early spring, particularly when green vegetation has not yet emerged. Groundhogs are not heavy bark-eaters the way porcupines or beavers are, but they will gnaw on young bark and nibble on emerging buds when their preferred food is scarce. This early-spring period is actually when their food intake is at its lowest, so even these less-preferred foods are consumed in modest quantities.2Journal of Mammalogy. Seasonal Variations in the Food Consumption of Woodchucks (Marmota monax)
Seeds and nuts are not a major part of the groundhog diet, but they are not completely ignored either. Groundhogs have been observed eating seeds from grasses and wildflowers. They are not hoarders or cache-builders in the way squirrels are, so seeds tend to be consumed incidentally as part of a broader foraging session rather than specifically targeted.
Insects and Animal Protein
People sometimes assume groundhogs are strict vegetarians, but that is not quite right. Their diet includes a small proportion of insects.1ScienceDirect. Dental Pathology of the Hoary Marmot (Marmota caligata), Groundhog (Marmota monax) and Alaska Marmot (Marmota broweri) Grasshoppers, grubs, beetles, and caterpillars all turn up in their diet on occasion. Whether this insect consumption is deliberate targeting or incidental ingestion while eating plants is debated, but given that groundhogs actively forage in grassy fields where insects are abundant, some combination of both seems likely.
There are scattered anecdotal reports of groundhogs eating bird eggs, snails, or even small nestlings, but these behaviors appear to be uncommon and opportunistic rather than a reliable part of the diet. The vast majority of what enters a groundhog’s digestive system on any given day is plant material. Characterizing them as “herbivores that occasionally eat insects” is closer to the truth than calling them omnivores in any robust sense.
How Their Appetite Shifts Across the Year
One of the most striking things about groundhog eating habits is how much they change with the seasons. Groundhogs are true hibernators, and their annual cycle of gorging and fasting shapes everything about when and how much they eat.
Food intake in adults is lowest in March, when groundhogs are just emerging from hibernation. It climbs to a peak in May, then gradually declines through the summer months. Some individuals show a temporary increase in food intake in late autumn before entering hibernation.2Journal of Mammalogy. Seasonal Variations in the Food Consumption of Woodchucks (Marmota monax) This pattern means that May and June are the months when groundhogs are eating the most and, consequently, causing the most damage to gardens and crops.
The late-summer and autumn decline is not because food is unavailable. Rather, it reflects a biological shift controlled by hormonal signals. As fall approaches, groundhogs transition from a hyperphagic state, where they are eating heavily to build fat reserves, to a hypophagic state, where appetite drops off steeply even though food remains abundant. Research on this transition has found that leptin, a hormone produced by fat tissue, plays an important role. In hypophagic animals preparing to hibernate, circulating leptin levels in the blood are significantly higher, acting as a satiety signal that tells the brain to stop eating.3PubMed Central. Hypothalamic gene expression underlying pre-hibernation satiety Essentially, the groundhog’s own body chemistry flips a switch from “keep eating” to “you have enough fat, stop now.”
This matters practically because the timing of gardening and the timing of peak groundhog hunger overlap almost perfectly. Spring planting coincides with the period when groundhogs are most motivated to eat, and the tender young shoots of a new garden are exactly what they prefer.
How Their Digestive System Shapes Their Preferences
Groundhogs are hindgut fermenters, meaning they rely on microbial fermentation in their large intestine to break down fibrous plant material and extract energy from it. This is the same basic digestive strategy used by horses and rabbits, as opposed to the multi-chambered ruminant system of cows and deer.
Because hindgut fermentation is the primary way groundhogs wring nutrition from tough plant fibers, maintaining the right mineral environment in the large intestine is essential. Research on northern rodents has found that woodchucks maintain extremely high concentrations of calcium and magnesium in the large intestine, which supports the microbial community that carries out fermentation. For animals eating fibrous diets that are naturally low in minerals, minimizing fecal losses of important nutrients is also critical.4Pergamon (ScienceDirect). Mineral concentrations in the alimentary tract of northern rodents and lagomorphs
This digestive setup helps explain some of their food preferences. Groundhogs gravitate toward plants that are relatively easy to ferment and nutrient-dense. Legumes like clover and alfalfa fit this profile well because they are higher in protein and more digestible than many grasses. Conversely, extremely tough, high-lignin woody material is harder for them to process efficiently, which is why they prefer succulent green leaves and stems over bark and wood whenever they have a choice.
Foods Groundhogs Tend to Avoid
Groundhogs are not indiscriminate eaters. They consistently pass over certain plants, and knowing which ones they avoid is useful for anyone trying to protect a garden.
- Strong aromatics: Plants with intense scents, such as lavender, sage, rosemary, thyme, and mint, tend to be left alone. These plants contain volatile oils that groundhogs find unappealing.
- Alliums: Garlic, onions, chives, and leeks are generally safe from groundhog damage. The sulfur compounds that give these plants their pungent flavor act as natural deterrents.
- Nightshade family leaves: While groundhogs will eat ripe tomatoes and peppers, they typically avoid the leaves and stems of tomato, potato, and eggplant plants, which contain toxic alkaloids like solanine and tomatine.
- Strongly bitter plants: Rhubarb leaves (which contain oxalic acid), daffodils, and other bitter or toxic ornamentals are avoided. Foxglove and lily of the valley, both highly toxic, are similarly left alone.
- Very fibrous or tough material: As their digestive system suggests, groundhogs prefer tender growth and generally avoid mature, woody stems and heavy bark when fresher options are available.
These aversions are not absolute. A very hungry groundhog in early spring, when little else is available, may sample plants it would normally avoid. And individual groundhogs vary in their willingness to try unfamiliar foods, so no plant is perfectly groundhog-proof. But as a group, the plants listed above are consistently low on their preference list.
How Predation Risk Changes Where They Eat
A groundhog’s diet in theory and its diet in practice can differ because of a factor that has nothing to do with nutrition: fear. Groundhogs and their close relatives in the marmot family are prey animals, hunted by coyotes, foxes, hawks, and dogs. This means they do not simply walk to the tastiest food patch and eat. They balance food quality against the risk of being caught in the open.
Experimental research on marmots has shown that when they forage farther from their burrows, they take substantially longer to begin eating, increase the frequency of their vigilance bouts (head-up scanning for predators), and shorten the duration of each vigilance bout, suggesting a heightened state of alertness. Their perception of risk clearly increases with distance from the burrow, and decreases when other individuals are nearby.5Ethology. Do Yellow‐Bellied Marmots Perceive Enhanced Predation Risk When they are Farther from safety? An experimental study In practical terms, this means a groundhog will preferentially eat whatever grows near its burrow entrance, even if better food exists further away.
Research comparing how different herbivores choose food patches in relation to their burrow refuges reinforces this point. Among small burrowing herbivores, proximity to the burrow is a genuine factor in food-patch selection, though the strength of this preference varies by species and by how exposed the foraging area is.6PubMed Central. Selection of food patches by sympatric herbivores in response to concealment and distance from a refuge For your garden, this has a direct implication: if a groundhog has established a burrow within about 50 feet of your vegetable beds, it does not need to be brave to eat your lettuce. The food is already inside its comfort zone. Discouraging groundhogs from burrowing close to the garden is often more effective than trying to make the plants themselves unappealing.
Protecting a Garden From Groundhog Feeding
Given that groundhogs eat many of the same vegetables people grow, coexistence requires some strategy. Fencing is the most reliable method. Groundhogs are capable diggers but not great climbers, so a fence made of hardware cloth or welded wire that extends at least three feet above ground and is buried about a foot into the soil can be highly effective. Bending the bottom of the buried portion outward in an L-shape makes it harder for them to dig underneath.
Planting the aromatic and allium-family deterrent plants mentioned above as a border around a garden can reduce casual browsing. Some gardeners interplant garlic or strong herbs among vulnerable vegetables to make the whole patch less inviting. These approaches work better as supplements to fencing than as standalone defenses.
Repellent sprays based on capsaicin (hot pepper), predator urine, or castor oil are sold widely, and some gardeners swear by them. Their effectiveness varies, and most need reapplication after rain. The evidence for any single repellent being consistently effective across different groundhog populations is thin, so treating them as one tool among several rather than a silver bullet is realistic.
Live-trapping and relocating groundhogs is legal in some jurisdictions but regulated in others. Before attempting it, check your local wildlife regulations. Relocated groundhogs often do not survive well in unfamiliar territory, so prevention and exclusion are generally more humane approaches than removal.
What Groundhogs Eat in Suburban and Urban Settings
Groundhogs have adapted well to human landscapes, and their diet in suburban areas can look a bit different from their diet in fully wild habitats. In neighborhoods, they supplement their natural plant diet with garden crops, ornamental flowers, and the occasional compost-pile raid. They are attracted to areas with short grass (which gives them good sightlines for predator detection) and abundant clover, making well-maintained lawns surprisingly good groundhog habitat.
Pet food left outdoors, fallen birdseed, and fruit from backyard trees are all items suburban groundhogs encounter. While they are not as drawn to seeds and processed foods as raccoons or squirrels, a groundhog that learns where easy calories are available will return. Securing compost bins, picking up windfall fruit, and not leaving pet food outside overnight can reduce what attracts them.
One underappreciated aspect of suburban groundhog life is how their burrows benefit other animals. In developed areas where natural cover is limited, groundhog burrows serve as shelter for a wide range of species including rabbits, opossums, skunks, and even foxes. This ecological role does not change what groundhogs eat, but it is worth knowing because removing a groundhog and filling in its burrow can have ripple effects beyond just that one animal.
Comparing Groundhog Diets to Other Marmots
Groundhogs (Marmota monax) are one member of a larger marmot family that includes about 15 species across North America, Europe, and Asia. Their diets share a common thread: marmots as a group are plant-dominated feeders. A comparative study of marmot dental health noted that the hoary marmot, a western mountain species, is a generalist herbivore eating mainly leaves and flowers. The groundhog’s diet is described as similar but with the addition of that small insect component.1ScienceDirect. Dental Pathology of the Hoary Marmot (Marmota caligata), Groundhog (Marmota monax) and Alaska Marmot (Marmota broweri)
What distinguishes the groundhog from most of its marmot relatives is habitat rather than fundamental food preference. Most marmots live in alpine or subalpine environments where the growing season is short and plant diversity is limited. Groundhogs are lowland animals that occupy meadows, forest edges, and increasingly suburban environments where the plant diversity available to them is much broader. This wider menu means groundhogs can afford to be choosier about what they eat and still find plenty. It also means they are the marmot species most likely to come into conflict with human agriculture and gardening, simply because they share habitat with us more than any other member of the family.
Alpine marmots in Europe, for instance, eat alpine grasses and herbs during a very compressed summer growing season and must build fat reserves faster because their hibernation period is longer. Groundhogs in the temperate eastern United States enjoy a longer growing season and more varied plant options, which may partly explain why their seasonal eating patterns show that May peak followed by a gradual summer decline rather than a frantic sprint to fatten up.2Journal of Mammalogy. Seasonal Variations in the Food Consumption of Woodchucks (Marmota monax) Their biology is built for hibernation, but their environment gives them a more relaxed timeline to prepare for it.