Coping with Deer in Suburban Gardens
Esteban Herrera, Extension Horticulturist
College of Agriculture, Consumer and Environmental Sciences New Mexico State University
Deer are a joy to watch, and when the spotted fawns appear in June and July, few can resist a tender feeling for these graceful animals. Yet, where they are abundant, deer can be one of the most destructive pests of home gardens, landscape plantings and orchards. Buds and twigs are nibbled in winter, new growth is eaten in the spring, and leaves are browsed in the summer. In the fall, bucks rub bark and break down small trees and shrubs when removing the velvet from their antlers.
Deer primarily eat twigs, buds and leaves. However, they also will eat grass, young shoots of vegetables, flowers and bulbs. Among preferred foods are soft-needled and broad-leaved evergreens. Yew, juniper, fir, spruce, false-cypress and white pine are especially favored. Yews and spreading junipers can be eaten to the ground in one winter. Conifers with stiff needles, such as Austrian pine, are more likely to be left alone. Deer also like laurel and some viburnums. Other favorites are the various kinds of evergreen euonymus. Many evergreen ground covers, including pachysandra and periwinkle, are extremely vulnerable and generally cannot be grown in deer country.
Thorny plants generally are safe. However, roses do not stand much of a chance, because the young shoots are browsed before they develop thorns.
New shoots of deciduous azaleas are eaten in the spring, but they can survive if the leaves manage to mature and become hairy.
Forsythia, weigela and privet can be grown without difficulty. Cotoneasters generally are left alone, although the ground-hugging types are sometimes lightly browsed in winter. Lilacs seem to be moderately attractive and are eaten sporadically, mainly the young shoots in the spring.
Although low-growing shrubs are always ready targets, large shrubs become less vulnerable to browsing as they mature. One reason is that when they reach a certain size, they can afford to lose a few leaves and twigs. Another is that they become too tall for the deer to reach. The lower parts, however, may be thoroughly denuded.
The only certain protection for a large area against deer is an 8-foot high woven wire fence; deer will jump over anything lower. Small areas near a building often can be protected with a 4-foot fence, because deer usually will not jump into small enclosures.
New shrubs and trees should be protected with cages 4-feet high and 18 to 24 inches in diameter. Young trees are especially vulnerable to antler rubbing, for bucks prefer to rub trunks no more than an 1 or 2 inches thick. Trunks 4 inches or thicker can be safely left exposed. Small trees with 3 or 4 feet of clear trunk can be protected with a wire cage 6 inches across. An even simpler device is a pipe sunk into the ground right next to the trunk. With 3 or 4 feet of pipe above ground, rubbing is stopped completely.
An electric fence with two wires, one 18 inches and the other 36 inches above the ground, is effective in most cases. Although deer could easily jump over such a fence, they prefer to go under and, in doing so, will naturally touch the lower wire. Also, they often nuzzle an obstacle and with the upper wire at head height they are quickly stopped. Sometimes it is suggested that a third wire be placed about half way between the other two.
Few homeowners are willing to fence themselves in. So repellents may be an alternative. The most common are Hinder, Thiram (Arasan), bone oil, and two recent discoveries—Tabasco sauce and hair balls. None of these work perfectly. They are most effective in summer when the plants are in full leaf and lots of other browse are available. Effectiveness also depends on deer pressure; the more deer there are, the less effective repellents are.
Hinder, commercially used as a spreader-sticker for insecticides and fungicides, is the only chemical registered as a deer repellent in New Mexico. Hinder can be sprayed over the plants or painted on the bark of trees and tall shrubs. For protecting fruit trees, vines, vegetables, field crops and ornamentals, mix 1/2 to 1 quart of Hinder with 5 gallons of water and apply in a light-coverage spray. To apply by painting, mix equal volumes of Hinder and water and brush on trunks. Avoid overhead irrigation for at least 24 hours after application.
Thiram, actually a fungicide, and Tabasco sauce repel by taste. The sauce requires only 2 tablespoons per gallon of water, and a spreader-sticker is also needed to make it stick to the plant. It is effective for a short time. Thiram is very sticky and hard to spray; it is best applied with warm water. Both are sprayed directly on the plants. To be effective, the treatment must be repeated every two weeks. Thiram is not yet registered as a deer repellent in New Mexico and should not be used on any plants that will be consumed by humans.
Bone oil repels by odor. Not only deer, but many people find the smell objectionable. Bone oil kills plants if sprayed directly on the leaves; so it is sprayed on the ground around trees and shrubs or on a 10-foot wide strip around the area to be protected. To be effective, spraying is needed once a month and more often in winter, when the odor diminishes even faster.
Hair balls are small net bags filled with human hair; you may have to make a deal with your barber. They seem to be effective only when deer pressure is low. This repellent is seldom effective during the winter, for hair balls do not smell when the temperature is low.
Strips of burlap soaked in a solution of half bone oil and half water and hung on stakes next to young plants have been effective in spring and summer. They have to be redipped every six weeks or so. To protect large plants, the stakes have to be placed about every 1 to 2 feet around the plant. This unattractive sight limits their use around the house or garden.
Sometimes no repellent seems to work. If you live in deer country and want to grow vegetables or fruit trees, the only dependable methods of eliminating deer damage are fences and cages.
The information given herein is supplied with theunderstanding-that no discrimination is intended and no endorsement by the New Mexico Cooperative Extension Service is implied.
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Revised and electronically distributed April 2003, Las Cruces, NM.