BLESSINGS IN BLOOM: Rabbits and Voles and Deer, Oh My!

Lions and tigers and bears, oh my!” exclaimed a very concerned Dorothy in the classic 1939 film “The Wizard of Oz.”

Here in Colorado, gardeners are just as exasperated by our “wildlife vs. garden plants” situation. What are we to do? We plant wonderful flowers, shrubs and trees, we take good care of them, only to step outside one morning to find them in ruins. This is part one of a two-part series discussing wildlife and our Colorado gardens.  

Rabbits. Rabbits don’t like to stray far from their shelters, so try to reduce the possible rabbit homes around your yard. Rake away piles of brush and leaves, fill in abandoned burrows, and seal any holes under sheds or structures. If a rabbit doesn’t have a place to live or hide nearby, hopefully, it won’t stick around to eat. Rabbits will also breed much more if they have a good habitat available.

The most effective way to win the battle with rabbits is by excluding them from desirable plants. Place chicken wire or rigid polypropylene plastic tubes around tree trunks and stems of shrubs. Bury chicken wire at least six inches deep to prevent rabbits from digging and chewing below the tubes. The wire must have holes smaller than a rabbit head because they will squeeze through small spaces.

Diverting rabbits by spraying plants with repellents can sometimes be helpful. Effective products contain one of the following active ingredients: capsaicin (pepper extract), castor oil, ammonium salts, or predator, especially coyote, urine.

Deer. Although browsing deer are elegant to watch, they can cause extensive damage by feeding on plants and rubbing antlers against trees. Home landscapes can become their major source of food. Deer can pose a serious aesthetic and economic threat. Damage is most commonly noticed in spring on new, succulent growth. Because deer lack upper incisors, browsed twigs and stems show a rough, shredded surface. Damage caused by rabbits, on the other hand, has a neat, sharp 45-degree cut. Rodents leave narrow teeth marks when feeding on branches. Deer strip the bark and leave no teeth marks.

Frightening deer with exploders, strobe lights or tethered dogs typically provides only temporary relief. More practical management strategies include selecting plants unattractive to deer, treating plants with deer repellents, netting, tubing, and fencing.

The two types of deer repellents are contact repellents and area repellents. Contact repellents are applied directly to plants, causing them to taste bad. Area repellents are placed in a problem area and repel by their foul odor. Repellents are generally more effective on less preferred plants.

Apply repellents on a dry day with temperatures above freezing. Treat young trees completely. Older trees may be treated only on their new growth. Treat to a height 6 feet above the maximum expected snow depth. Deer browse from the top down. Hang or apply repellents at the bud or new growth level of the plants you wish to protect.

According to a study conducted by Colorado State University a spray of 20 percent whole eggs and 80 percent water is one of the most effective repellents. To prevent the sprayer from clogging, remove the chalaza or white membrane attached to the yolk before mixing the eggs. The egg mixture is weather resistant but must be reapplied in about 30 days. Deer Away – Big Game Repellent and coyote urine are also rated high in effectiveness.

Netting around individual seedlings are an effective method to reduce deer damage. Tubes placed around the trunks of larger trees will help prevent trunk damage. Tubes may not, however, protect trunks from damage when bucks use the trees to scrape the velvet off their antlers. Fencing may be required.

Adequate fencing to exclude deer is the only sure way to control deer damage. The conventional deer-proof fence is 8 feet high and made of woven wire. Electric fences also can be used.

Additional options include invisible mesh barriers, slanting deer fences, and single-wire, electric fences baited with peanut butter. The invisible mesh barriers are polypropylene fences of various mesh sizes, typically 8 feet high with a high tensile strength, that blend in with the surroundings. The baited fences attract deer to the fence instead of what’s inside the fence. They administer a safe correction that trains the deer to stay away. They are effective for small gardens, nurseries and orchards (up to 3 to 4 acres) that are subject to moderate deer pressure. For additional information on deer fencing and a list of deer-resistant plants, go to https://www.colostate.edu/ and search deer fencing and/or deer resistant plants. While you are there, browse the site. There is valuable, research based information for our area.