Controlling Animal Pests in Gardens and Landscapes

Dr. Leonard Perry, Extension Professor
University of Vermont

Effective control of animal pests is possible though your success will depend on your timing, method, and perseverance.  A control that works for your neighbor, or that worked for you last year, may not work this time around. You may need to try a variety of methods and devices and, if first you don’t succeed, try again. Remind yourself that animals may be clever and smart, but humans are smarter!

Here are some common animal pests found in the Northeast and some recommendations for control. None of these are fool proof, but all are worth a try to control pesky animals.

MICE AND VOLES: Although these rodents look similar and cause similar damage, they are only distantly related. Both live in grassy areas and leaf mulch and travel in tunnels. They feed on any vegetation, including bulbs and tubers, as well as bark on young trees and shrubs. Exclude them with barriers or trap at main runways with peanut butter bait or vitamin D (death results from calcium imbalance). Other repellents such as castor oil may help, as will cats or dogs.

If using a common poison bait trap or packet, be aware that cats or other animals may be attracted to the trap to feed on the bait, or birds and other large animals may be inadvertently killed by feeding on a poisoned small animal.

MOLES: Moles live in tunnels that, while helping to aerate soil, also provide passageways for other animals and may cause excessive soil disturbance and plant upheaval. Although moles help by eating insects like grubs, they also hurt by eating earthworms. Control them by eliminating the insects they feed on or trap as you would voles.

CHIPMUNKS: This rodent lives in tunnels or burrows and is adept at running up trees and shrubs as well as along the ground. Chipmunks feed on seeds, nuts, fruits, roots, bulbs, and despite their tiny size they can uproot new plantings. Trap them using peanut butter, oats, nut meats, or sunflower seeds.  Spray repellents on bulbs, or place jagged shells or stones in the holes when you plant bulbs. Fine-mesh plant cages will keep them out. Or get a cat or two.

TREE SQUIRRELS: Squirrels are an occasional problem as they like to nest in trees and will feed on fruit, nuts, insects, bark, and seeds. Protect new plantings with cages. Squirrels can be trapped and released using sunflower seeds, peanut butter, and raisins as bait.

RABBITS: Rabbits are a serious problem not just in the Northeast, but throughout the entire country. They live in grassy areas and thickets, feeding on vegetables, flowers, and tree bark during winter. They are active during the day year round in most areas. Your best bet is to fence them out with chicken wire or hardware cloth cages placed higher than snow level. Inflatable snakes or repellents, such as those used for deer, also may help.

GROUNDHOGS (WOODCHUCKS): These rodents (related to rats and squirrels) cause only occasional problems in the northern states, mainly to herbaceous plants. They live in burrows with two or more openings with mounds at entrances. You can find them feeding in early morning and late afternoon on grass, tender vegetables and flowers– especially pencil-thick stems like phlox, and occasionally on bark.  They don’t “chuck” on wood, this name coming from a native American name for this animal.

Your best bet is to trap them live (if legal) or fence them out with a three-foot high fence. Bury several inches in the ground to prevent them from tunneling under. You also can repel them with taste sprays applied to desirable flowers or by placing oily substances at hole entrances. If all else fails, you could insert poison gas cartridges in their holes and cover to kill.  Don’t use the latter around buildings, though, which they like to make holes alongside or under.

Live traps with release of animals a distance away may not be the best alternative as you may catch non-target animals.  For example, you may catch domestic cats, or even skunks.  Your community or state also may have regulations against relocating certain wild animals such as woodchucks. Be sure to know your local wildlife laws before you act. If trapping large live animals, use caution to prevent being bitten as many carry communicable diseases such as rabies.

Snap or leg hold traps are banned in most areas, though even if permitted they are not a good choice as it is a cruel and inhumane way for any animal to die. There’s also a good chance that you could catch a pet or worse, injure a child. Shooting is usually not permitted, and especially not in populated areas. You may choose to hire a wildlife specialist to catch and dispose of such large animals.

SKUNKS: Skunks live in rural, wooded areas where they feed on insects, small rodents, fruits, berries, and other vegetables. They are actually more of a nuisance because of their smell than from eating flowers, although they can carry rabies. Fence them out or trap (if legal) as you would groundhogs. If trapping live, bait with sardines or cat food. Be sure to wear protective clothing and eye goggles when handling skunks, and cover the cage with a tarp when transporting.

RACCOONS: Like skunks, raccoons generally are not a problem in flower gardens although if you have corn, be on the lookout for these masked marauders. They live in wooded rural or lightly populated areas in natural shelters such as hollow logs or near water. They feed on insects, small animals, grains (especially corn), seeds including bird seeds, vegetables, and other plant materials. Keep them out with a wire fence (about four feet high with another foot buried in the ground) or electric fencing, or trap (if legal) as you would skunks.

DEER: Deer are a serious problem throughout the country, even in populated areas. Being quite intelligent, with few natural predators and strict control laws, they can be difficult to control. Deer prefer wooded areas and tall grass and thickets. They eat most plants and the bark of woody plants.

Many deer controls are available, including various taste and smell repellents (deer have a keen sense of smell); light or noise emitters (must be moved often as deer are smart and learn quickly); or an electric fence baited with peanut butter (one taste won’t kill, but will deter deer). A key with such repellents is to move them, or rotate among various ones, every few days.

The best and often only solution, particularly if many deer and they are hungry, is exclusion with three-wire triangular or slanted fences, or eight- to ten-foot high deer fences of woven wire mesh or heavy fishing line strung at two-foot intervals up the posts. If using the latter, flag the lines as deer can’t see well and will try jumping through. For narrow or small gardens, a lower fence 5 to 6 feet high usually works as deer are afraid of getting trapped inside.

DOGS: Dogs can devastate gardens by running and romping. They also dig up soil and plantings and leave droppings. Keep them out with fences or repel with plant sprays designed specifically to deter dogs. Tie up your own dog or use invisible fencing to keep it from getting into areas you want to protect. Ask neighboring dog owners to keep their pets out of your yard.

CATS: While cats usually are good at keeping small rodent populations in check, they can be a problem if they dig up new plantings. Use repellents or lay chicken wire on new beds.