Garden pests bugging you? Extension Office has the answers!

Workshop shows residents how to deal with pesky critters

By Patty Unruh

The CSU Extension Office conducted a workshop June 22 to help mountain gardeners learn to deal with pests that may be destroying their gardens. Irene Shonle, CEO director/agent, informed a small class of interested residents and answered their questions about how to discourage pocket gophers, voles, and other critters, plus a variety of irritating insects.

Shonle reminded the participants that we share our land with the local wildlife and cannot simply “get rid” of them. Sometimes animals and insects do damage our gardens. The main idea of the workshop was that if it is not possible to live with the damage, then we must work on ways to exclude pests from our prize plants.

In general, there are a number of ways to exclude animals from yards and gardens, although no method is completely effective. Making one’s yard less attractive is the only long-term solution, Shonle advised.  Bears, squirrels, and other animals nibble on the bird seed we put in our feeders, so she recommended restricting seed feeding to the winter season. Removing brush piles and other protective cover where rabbits and ground squirrels like to hide may help; small animals will avoid open areas that make them more vulnerable to predators.

Young, small plants that have just been planted are very succulent to deer, rabbits, or ground squirrels. Folks may wish to stick with less palatable plant varieties, such as very aromatic or toxic plants, those with prickles and spines, or those with tough leaves or milky sap. No list is foolproof, though, and Shonle acknowledged that a hungry animal will eat just about anything, including poisonous plants.

If animals get too pesky, Shonle said relocating or exterminating them may be a solution. However, check with the Colorado Parks and Wildlife. Certain animals may be killed if they are damaging property, but a permit may be needed. The only animals allowable for relocation are tree squirrels, cottontail rabbits, and raccoons.

Relocating wildlife may sound like a nice idea, but an animal could become disoriented in a new location. It may try to come back to its original habitat, getting run over as it crosses a street. If the new area is good for food and shelter, the animal could be competing with many other animals and have to fight to the death for its needs. If the new habitat is not that good, water and shelter may be difficult to find. The spread of disease is also a risk.

Burrowing Animals

Burrowing animals can wreak havoc on a garden. Pocket gophers are problematic because they live underground and feed on plant roots, which kills the whole plant. Late summer is their most destructive period, when they are pushing their young out to live on their own and the young are making new burrows.  A mound of soil will be visible, which is plugged closed to keep temperature and moisture steady and to keep out predators. In the spring after snow melt, sausage-like trails of soil called eskers reveal the presence of gophers.

To try keeping gophers away, dig a trench around the garden, line it with wire mesh, and pack soil on top of it. A gardener could even try the “Cadillac” version—putting mesh under the entire garden bed.

To exterminate gophers, Shonle suggested poison-peanuts pellets, which act as bait to attract the gophers, or a poison embedded in a wax block. These may be found at hardware or home improvement stores and are relatively fast acting. A quick death is more humane than slow torture, and all the poison is contained below ground, so the poison does not affect other animals.

Voles are other destructive critters that remain active all year round. They form short, shallow burrows and eat a wide variety of plants above ground, including seeds, grasses, and soft bark. Protect trees with plastic mesh and keep vegetation low in summer, since voles like to hide in tall grass. Repellents such as blood meal, castor oil, or coyote urine can be effective at keeping them away, or they may be exterminated with mousetraps. Shonle doesn’t recommend poisons, because voles feed above ground, and there is the possibility of poison going up the food chain.

Rabbits and Squirrels

Rabbits have a clean bite when chewing plants, making it look as though the plant was pruned. Like voles, they girdle trees and also find garden vegetables quite tasty. They don’t jump high, so it is actually easy to exclude them from a garden with a two-foot high wire mesh fence, buried about three inches into the ground. Raise garden beds a few inches, place flowers in window boxes, mow grass and weeds, and remove brush piles. Use wire mesh to block off low decks and porches, which tend to become “rabbit hotels.” Rotten eggs, garlic, and hot pepper have a good repellent effect. Shonle warned that toxicants and fumigants are illegal.

Ground squirrels and chipmunks eat seeds, birdseed, berries, flowers, and bugs. They may be controlled by putting a smooth-sided trough around precious plants to prevent climbing. Squirrels may be shot and left out for a coyote meal, as long as lead-based pellets are not used.

Deer and Elk

Deer eat a huge range of plants and like new growth and tree bark. When they eat bark, it has a rougher, more shredded look than rabbit tooth marks. Tree protectors, up to a height of six feet, work well for deer and elk.

For the garden, try a polytape fence, a special electrical fence that is baited with peanut butter. The deer are scared off by a shock when they try to feed. Another idea is to construct a four-foot double fence, with the thought that a deer and can’t jump both high and wide.

Shonle suggested a super-hot sauce concoction as a repellent for deer, noting that weak hot sauce doesn’t work. Spray it on plants that you want to protect. The odor dissipates for humans, but not for deer.

A new motion-activated device has a taped cry of a deer in distress. When a deer hears the cry, it will leave.


Insects don’t generally cause long-term harm, but they can damage some vegetable crops. Keep cabbage worms controlled with the use of floating row cover. Flea beetles are also common. Keep them off with floating row cover, or suck them up with a vacuum. Aphids may be managed with water spray, and again, floating row cover works well if the aphids are not already on the plants. Slugs may be handpicked daily and squashed. Insects may also be discouraged with insecticide soap.

Floating row cover, a light, spun polyester cloth, is a great tool for mountain gardeners, Shonle advised. The cover protects the garden from most insects and wildlife, lets water and sun through, reduces moisture loss, and protects plants from frost. It may be obtained at garden centers, nurseries, or on-line.

Tent caterpillars, in their white cocoons, are found in a variety of different trees. Birds will eventually take care of them, but if preferred, they may be cut down and burned (except now, when there is a fire ban on), or placed in a freezer until dead.

If ants are a problem, Shonle recommended Borax. Put it out as bait; the ants will take it down into their mound and poison the whole colony. She emphasized, however, that ants are a species important as food to many creatures.

As with many other animals and insects, “pick your battles,” she advised.

To get more questions answered, call the CSU Extension Office in Gilpin County at 303-582-9106.

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