UNIVERSITY PARK – Deer and rabbits can wreak havoc on ornamental plants during the winter, but outsmarting them is easy with some precautionary measures. “These animals are the primary trouble-makers in Pennsylvania, though other animals can cause just as much winter damage to plants that are expensive to replace in their hunt for food,” said Jim Sellmer, associate professor of ornamental horticulture in Penn State’s College of Agricultural Sciences.
An economical approach to deer-proofing the lawn is individual fencing. Unless people have large areas of new growth that they want to protect from deer, individual fencing is a more practical method of protecting their plants during the winter, and is cheaper than fencing in the entire yard. “People often enjoy seeing deer in their yards and don’t want to eliminate them completely with a large fence,” Sellmer said. “Individual fencing lets deer into the yard without causing damage to plants.”
“Most deer are browse eaters, preferring shoots and leaves to grass,” he explained. “Deer will try plants out for taste, so don’t be surprised if you find your plants ripped from the ground but barely eaten. Therefore, you want to protect both new and mature trees and shrubs. A deer can reach over fencing, so make sure it is high enough that no part of the plant is accessible to the deer. Any tree or shrub under 3 feet tall needs to have a fence surrounding it that is several feet higher than the plant.”
Fence posts should be driven into the ground about 4 feet from the tree or shrub to prevent deer from leaning over the fence to reach the plant. Plastic or woven wire mesh is then attached to the stakes to form a barrier between the plant and the deer. “You should inspect your fence at least one time per week, especially after a heavy snowfall,” said Sellmer. “Once the snow hardens, you may need to make your fences taller as deer can walk across the packed snow and eat the tops of trees and shrubs.”
For those who would rather fence their entire yard than just individual plants, make sure the fencing is at least 7 feet tall to prevent deer from jumping over it. “Fencing your entire yard is expensive but has the benefit of keeping out other animals that can cause damage besides deer,” said Sellmer.
An alternative to fencing the plants or yard is the use of chemical deer repellents. “Deer don’t like the taste or smell of repellents,” said Sellmer. “However, most repellents wash off from rain or snow and extremely hungry deer won’t be deterred.” Repellents will need to be applied routinely but can be made from household items, such as a mixture of spoiled eggs and water, or purchased from garden centers.
An easier approach to fighting deer is to plant trees and shrubs that deer don’t find delicious. “Some trees resist deer damage, such as pines, spruces, box elders and black locusts, but no plant can be entirely deer-proof,” Sellmer said. “Some deer-resistant shrubs you can consider planting are hollies, rhododendrons, barberries, lilacs and tree peonies.”
While deer present dangers to trees and shrubs, rabbits can cause just as much damage by gnawing off bark. “Since rabbits can only reach up about 24 inches they’re much easier to control than deer,” he said.
Rabbits, like deer, can be deterred from nibbling on plants by constructing a fence. “Rabbit fences are made in the same way as a deer fence but the bottom of the fence should be buried 2 to 3 inches below the ground so rabbits can’t tunnel beneath it,” said Sellmer.
“Make sure that your rabbit fencing doesn’t have holes larger than 1 inch and that the mesh is firmly attached to the stakes. Rabbits can push against the mesh and eat the plant right through the holes, so plant the stakes firmly in the ground to prevent movement.” Rabbits also can be dissuaded by wrapping plants with a protective fabric. The weatherproof wrapping can be wound around the trunk but must be checked regularly to make sure it is still intact.
Fencing in larger areas also is a possibility, though it is important to remember to bend the fence at a 90-degree angle and bury it in the ground. “All rabbit fencing needs to be at least 24 inches tall regardless if it’s plastic wrapping, individual fencing or fencing in a large area,” said Sellmer. “With the snowy season starting, make sure the fence is always 24 inches higher than the snow and check large-area fencing regularly. Rabbits may not be able to escape if they get caught inside.”
Repellents can be used for rabbits just as for deer, although if hungry enough, not even a bad taste will stop them. “Similarly, both become tolerant to the taste and smell of repellents, so switching the repellent type is important during the season,” said Sellmer.
“Deer and rabbits don’t have to be troublesome with a few precautionary measures,” said Sellmer. “You’re never going to stop them completely but you can cut down on your damage. By protecting young trees and shrubs, the problem will fade away as the trees grow.”