Minimizing Deer Damage to Residential Plantings

Printable version of article

By Chester Hill, Roosevelt County Extension Agent; and Jim Knight, Extension Wildlife Specialist (retired)

Deer are probably the most widely distributed and best recognized large animal in North America. Two species most common in Montana are the white-tailed and mule deer.

Deer habitat includes wildlands, agricultural areas, and, in some cases, residential areas. Deer favor early vegetation stages that keep brush and sapling browse within reach. Dense cover is used for winter shelter and protection. Because deer are so adaptable and residential areas sometimes provide suitable habitat, deer pose challenges to homeowners.

Damage identification is not difficult. Because both mule deer and white-tailed deer lack upper incisors, deer often leave a jagged or torn surface on twigs or stems that they browse.

Homeowners can be frustrated in keeping these pests away from their trees or garden plants. Scare devices, exclusion and repellents have a place in deer damage control. Initial selection of plantings may provide the best remedy to prevent deer damage.

Cultural Methods and Habitat Modification

Deer damage to ornamental plants can be minimized by selecting landscape and garden plants that are less preferred (Table 1). MontGuide 9521 AG, "Deer-resistant Ornamental Plants" also provides suggestions.

In addition to planting tolerant plants, harvesting garden crops as early as possible reduces the period of vulnerability to deer. Planting susceptible crops as far as possible from wooded cover will also reduce deer damage.

Repellents

Repellents are well suited for use in orchards, gardens and on ornamental plants. High cost, limitations on use, and variable effectiveness make most repellents practical only for certain situations. Repellents are moderately effective for short periods and usually require multiple applications.

"Contact" sprays are applied directly on the plant and repel by taste. These are most effective on trees and shrubs during the dormant season.

"Area" repellents are applied near the plants to be protected and repel by odor. They are usually less effective.

During the winter dormant season, apply contact repellents on a dry day when temperatures are above freezing. Be sure to treat to a height of six feet on trees. The effectiveness of repellents depends on how much it rains and how hungry the deer are. Deer-Away®, Hinder®, Thiram®, Miller's Hot Sauce®, Tankage®, and Ro-pel® are some of the repellents available.
Tree Protectors

Tree protectors are available to put around tree trunks. Use Vexar®, Tubex®, plastic tree wrap, or woven-wire cylinders to protect young trees. Usually four feet of woven wire cylinders can keep deer from rubbing tree trunks with their antlers.

Exclusion

In some situations exclusion may be the most logical method of preventing deer damage. In backyard gardens, where deer depredation may be a constant challenge, a permanent fence may be cost effective. In orchards and around ornamentals, electric fence may be a solution. Several fencing designs are available to meet specific needs.

Permanent Woven-Wire Fencing

Woven-wire fences are used for year-round protection of areas subject to high deer pressures. These fences are expensive and difficult to construct, but easy to maintain. Woven-wire fences were used most often before the advent of high-tensile electric fencing. Cost, excluding labor, is about $2 to $4 per linear foot. The high cost has resulted in reduced use of woven-wire fences.

To build a deer-proof woven-wire fence, follow the steps below.

1. Set rigid corner assemblies where necessary.
2. String a light wire between two corners and apply light tension.
3. Set 16-foot posts along the wire at 40-foot intervals, to a depth of 4 to 6 feet.
4. Roll out an 8-foot roll of high-tensile woven wire along the line posts. Attach one end at ground level to a corner post with steel staples.
5. Apply tension to the wire with a vehicle or fence strainers and attach the wire to line and corner posts with steel staples.
6. Repeat steps 4 and 5 as necessary around the perimeter of the fence.
7. Attach two strands of high-tensile smooth wire to the top of the fence to raise the height of the entire fence to 9 to 10 feet.

Electric Fencing

Vertical electric fences are effective at protecting gardens and orchards from moderate to high deer pressures. Because of the prescribed wire spacing, deer either attempt to go through the fence and are effectively shocked or they are physically impeded by the barrier. Vertical fences use less ground space than three-dimensional fences, but are probably less effective at preventing deer from jumping over them. A wide variety of fence materials, wire spacings and specific designs are available. Costs, excluding labor, range from $0.75 to $1.50 per linear foot.

To build an 8-wire vertical deer fence (see Figure 1 below), follow the steps below.

1. Install rigid corner assemblies where necessary.
2. String a 121/2-gauge high-tensile wire around the corner assemblies and apply light tension.
3. Set 8-foot line posts along the wire at 33-foot intervals.
4. Attach a wire to insulators at 8 inches above ground level and apply tension.
5. Attach the remaining wires to insulators at the spacing indicated in Figure 1 and apply tension.
6. Connect the second, fourth, sixth and eighth wires from the top to the positive (+) post of a well-grounded, low-impedance fence charger.
7. Connect the top, third, fifth and seventh wires directly to ground. The top wire should be negative for lightning protection.
8. Clear and maintain a 6- to 12-foot open area outside the fence so deer can see the fence.

Maintenance includes weekly fence inspection and voltage checks. Applying a molasses-peanut butter mixture to the hot wires using a mop glove will encourage deer to touch the fence with their noses or tongues. This will provide greater repellent effectiveness.

Other Methods

Homeowners often come up with ideas that are unique to their situations. Tying a dog near damaged areas or using motion sensing scare devices will sometimes work. The sooner deer are discouraged from damaging your plantings, the more likely they are to stay away.

This information is for educational purposes only. Reference to commercial products or trade names does not imply discrimination or endorsement by the Montana State University Extension Service.