Gardening: Critters invading your landscape?

You plant bulbs and perennials in fall, in anticipation of a colorful spring, then see all that new growth disappear before you have a chance to enjoy the blooms! You’ve got critters. Every gardener has suffered from critters nibbling, gnawing and digging through the garden. What to do? Cures for wildlife issues don’t exist; however, steps can be taken to identify the culprit and minimize damage to the landscape.

By Kathi Taylor
Colorado State University Extension Master Gardener in Larimer County

Raised tunnels in grass and spongy spots are indicative of burrowing rodents, most often voles or pocket gophers. Though unsightly, lawn damage is usually minimal and may be reduced by shorter mowing, fertilizing and weed control. With mild infestations, aeration may be a plus—something to think about when your foot sinks into a soggy tunnel. Vole damage on ornamental shrubs, trees and orchards is characterized by girdling of trunks and gnawed irregular bark patches. Pocket gophers often snip stems of small shrubs and trees near their tunnels. This villain can also pull a small annual or perennial into his tunnel from below.

Rodents may be excluded from orchards and ornamentals by burying hardware cloth or plastic mesh three to six inches below ground level and projecting the barrier 18 inches above the ground. Repellents containing thiram (Nott Chew, Bonide Rabbit-Deer Repellent, Science Deer and Rabbit Repellent) and Capsaicin, a product made from hot peppers, may be somewhat effective; read labels for use on food crops. Mouse snap traps set at the end of tunnels are a possible control for small populations. In desperation, poison grain baits may be utilized in grassy areas. Read labels carefully and be aware of the lethal potential to pets, birds, humans and other animals.

Peter Cottontail is not the gardener’s friend. Rabbit damage is characterized by a sharp 45-degree angle feeding cut. In winter, rabbits will feed on fruit tree bark and ornamental plants—evergreens are favorites. Tulips and roses, including other rose-family plants (apple, raspberry, cherry, plum and mountain ash), are munched regularly in spring and summer. Rabbits are easily excluded from gardens with wire fencing buried shallowly in the soil. Holes in fencing should be no larger than 1/2 inch. Plastic tree wraps are effective, as is repellent containing thiram.

Some of the most destructive and pervasive garden pests in urban and rural gardens are deer. Though their grace and beauty is lovely to behold, the “Bambi syndrome” is quickly compromised when witnessing a garden browsed by deer. Ragged wounds characterize deer damage. Lacking upper incisors, deer tear branches and bark from trees and shrubs, decimate vegetable crops, and wipe out tulips and roses. In deer prone areas, eight-foot fencing is the only sure deterrent. In most cases, an eight-foot fence isn’t reasonable for gardeners, so repellent is a possibility. Some with promise are those using egg solids (Deer-Away, MGK Big Game Repellent) or ammonium soaps. Another option would be to plant enough vegetables for both your family…and deer.

A reasonable cultural control for deer is planting infrequently browsed plants. However, if food is scare, they will eat virtually any plant. A few of the less palatable perennials include the salvia family, daffodils, larkspur, lavender, coneflowers, Russian sage and most herbs. Trees and shrubs include Apache plume, blue-mist spirea, juniper, Douglas-fir, lilacs, silver buffaloberry, sumac and quince. Drought tolerant plants tend to be less browsed—another reason to be water thrifty when planning a landscape.

Although wildlife issues in the garden are challenging, it is possible to decrease frustration and wildlife damage by identifying and taking steps to discourage the critters in the garden. Happy gardening!

For more information on managing wildlife, visit the Colorado State University Extension website at and search for Fact Sheets #6.507, #6.515 and #6.520 on voles, pocket gophers and deer damage, respectively.

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