How to manage deer damage on trees and other plants

• White-tailed deer spend more time feeding than any other activity.
• Although they are mainly browsers, their diet varies seasonally.
  • In spring and early summer, they mostly eat the new growth of grasses and leafy plants.
  • In autumn, they consume mast, such as acorns, as they build fat reserves for winter.
  • Food is scarce during winter and deer will eat any available vegetation including dried leaves, sedges, grasses, mushrooms and woody plants.
• Deer are also common visitors in agricultural fields.
  • In areas where crops like corn, soybeans, alfalfa or grain are grown, crops can be up to 78 percent of a deer’s diet.

Deer are creatures of habit. They prefer the safety of known foraging grounds to unfamiliar areas. They will often use specific paths for areas they visit often. 

Deer are extremely persistent when foraging for food.

• They can jump up to 12 feet high and 30 feet long, as well as crawl through gaps as small as seven and a half inches.
• They quickly become used to strange sights, smells and sounds, including many deterrents.
• Deer also will continually test for weaknesses in barriers like fences.

Winter behavior

In the northern U.S. and Canada, deer experience lots of stress in winter. Deep snow makes it difficult to find food and escape predators, and cold temperatures place greater strain on their metabolism.

Many deer in these regions will migrate to winter “yards,” or areas that continue to provide forage in winter and offer some shelter from the elements. Large herds of deer will travel to these yards and remain there for the winter before leaving in the spring.  

Spring behavior

Landowners often see an increase in damage in the early spring, when deer fat reserves are at their lowest. During these times of high stress, hungry deer will seek food of higher nutritional value in gardens, agricultural fields and orchards.

Other stressful conditions for deer include drought, flood, overpopulation and competition with other browsing animals, such as rabbits.

Deer damage to ornamental plants is very frustrating. You can minimize the damage they can do by avoiding plants they prefer and instead use the plants listed in the table below that deer avoid due to toxicity, fragrance or texture.

Using fencing to prevent deer from reaching vulnerable areas is the most effective way to prevent damage. Fencing can be permanent or temporary depending on the severity of the damage and seasonal patterns. But it also can be the most expensive option depending on the type of fence installed, the size of the area and the installation requirements.

A fence is only as strong as its weakest point. Ensure that gates are strong and well designed, and check the entire fence frequently for damage.

If you decide to install fences on your property, there are several options available. The most common types of fences are woven wire or wire mesh and electrified fences.

Woven wire fences

• Woven wire or wire mesh fences offer long-term protection for larger areas. 
• These fences are durable and flexible enough to be installed on uneven terrain. 
• The flexibility of the wires also minimizes injury to deer that become entangled in the fence. 
• Fences need to be at least 8 feet tall to protect larger areas.  
• Micro-exclosures that are 8 x 16 feet and only 50 inches high have successfully excluded deer.  
• Check local regulations before installing fences, many areas have height and setback restrictions.
• Read more about protecting plants from deer.

Electric fences

• Electric fences can be a long-term or temporary solution.
• They can be made of electrical wire or polytape — either are effective at deterring deer from entering certain areas.
• Tying flags to the wires will make the fence more visible to deer and human visitors.
• Peanut butter can attract the deer to the fence and the light shock will deter them from coming near the fenced area again.
  • Spread peanut butter on aluminum foil and fold it over the wires.
• Check local regulations before installing electric fencing as they are prohibited in some areas.

Using fishing line for fencing

• Fencing made from heavy fishing line is a low-effort and visually unobtrusive method that may offer short-term protection for some garden beds.
• High-test (30 lb or more) monofilament fishing line is tightly strung around the garden bed, 30 to 36 inches above the ground, and about 2 feet beyond the outside edge of the garden.
• Use strong corner posts and regular inspections to be effective.
• This technique acts like a repellent.
  • A deer approaching a garden after dark will encounter an unseen force pressing against its body, causing it anxiety and discomfort.
• It is ineffective when deer density is high or where deer forage during the day.

Protective structures like tree shelters, tree tubes, bud caps, wire cylinders and netting are more effective at protecting individual plants or very small areas. They are not permanent structures, and should be removed when the trees are large enough to withstand browsing, or when they are not seasonally necessary. 

Some alternatives are designed to degrade naturally, but these are often more expensive and do not always degrade as expected. Installation, maintenance and removal are too time and labor intensive for larger areas. Take care during installation as these structures can damage plants if improperly installed.

Shelters and tubes

Shelters and tubes are structures that surround plants and are staked into the ground. They can prevent browsing on vulnerable seedlings and shrubs, or protect the trunks of larger saplings from antler rubbing damage if tall tubes are used.  

Fencing and tree guards

Fencing or tree guards are better protection from larger bucks and should be in place from August through December to protect plants from antler rubbing.

Bud caps

Bud caps are small squares of newspaper or cardstock stapled around the terminal buds of trees to protect them from deer browse. They are mostly used for conifers during winter and do not prevent the deer from browsing on the lateral or horizontal branches. 

Wire cylinders

Wire cylinders made of wire mesh surround plants to prevent browsing. Cylinders should be at least 6 feet taller than the snow depth to afford full protection.

Another way to reduce damage from deer is to make your gardens and landscaping less attractive than the surrounding habitat. Deer will eat almost any plant if they are under enough stress but will avoid less tasty plants under most conditions. Though this method is not very successful on its own, it is relatively easy and can be combined with other methods to increase their effectiveness.

Replace plants that attract deer with less desirable plants, or surround palatable plants with plants that are less attractive to deer. For example, deer tend to avoid lilacs and red pine. The Chisago County Master Gardeners have compiled a list of deer resistant plants, but deer may browse nearly any plant during times of high nutritional stress such as winter. 

Plant placement can have an impact 

• Place plants that are desirable for deer closer to areas with a lot of human activity.  
• Place less desirable plants closer to areas deer feel secure in, such as a nearby woodlot.

Do not feed deer

• Human-fed deer become used to foraging near homes and in gardens and are more likely to cause damage to plants. 
• Feeding hungry deer late in the winter may seem humane, but can actually harm or kill them. 
  • Their digestive system is not prepared for high-energy food at that time of year. 
  • Deer are naturally adapted to survive the winter without human aid.  
• Supplemental feeding is expensive, provides improper nutrition, increases the spread of diseases, and can increase the population to unwanted levels. 

Repellents are a short-term solution and usually work best when used on less palatable plants in small areas. 

• Apply repellents as early as possible to protect plants before deer begin to browse on them. 
  • Reapply repellents often, as new growth will not be protected. 
  • Repellents should be applied on dry days with temperatures above freezing. 
  • Apply the repellents from about 6 feet above the maximum snow depth.
  • Treat trees and shrubs from the tops down, which is the pattern that deer browse. 
• Change repellents periodically so that deer do not encounter one repellent repeatedly and become habituated. 
• Repellents produce a smell that frightens deer, like predator urine, or condition deer to avoid the plant by making them feel unsettled after eating it, like capsaicin.
• The two types of repellents are contact repellents and area repellents. 
  • Contact repellents are applied directly to plants and make them taste unpleasant to deer. 
  • Area repellents deter deer with unpleasant odors and are placed in areas where deer are undesirable. 
• There are many repellants formulated for deer (be sure to read and follow the label directions as well as match the repellent with your application situation). 
  • The Nuisance Wildlife Repellant Handbook offers a list of repellents and their use.
• Many people also use home remedies like human or pet hair, perfumed soaps, mothballs and bone tar meal, but their effectiveness has not been tested. 

• Hazing, or frightening deer away from vulnerable areas, is another short-term solution. 
• Most hazing methods frighten deer with sudden, loud noises such as firearm blanks or gas exploders set to irregular intervals. 
  • Motion-activated sprinklers, lights or noisemakers, such as a radio, are other effective options.
• Keeping dogs in the area you wish to protect from deer also can be effective, but dogs also are liable to cause damage and require care. 
• Unfortunately, deer quickly become used to hazing techniques.

One of the most effective methods of preventing deer damage reducing the population during the regulated hunting season.

• Fewer deer means less damage, and less pressure on the surviving animals to feed in areas we want to protect. 
• Hunting also can help prevent starvation and disease transmission in wild deer, as these both increase at high deer densities.

If you are not a hunter, you can establish relationships with archery or firearm deer hunters in your area and grant them access to your property.

• Special archery hunts have successfully reduced deer densities in developed areas but often require local government support.
• Many municipalities restrict or ban hunting. Contact your local government officials to urge them to manage the deer herd.
• For more information on setting up partnerships, please contact your local Minnesota Department of Natural Resources Area Wildlife Office.