MSU Extension

Landscape and garden damage caused by deer is a common issue many homeowners have, and Michigan State University Extension horticulture educators and Master Gardener hotlines receive questions year-round on this topic. It’s usually after the event and there may be little to offer other than sympathy. However, smart gardeners are those who think ahead. If this happened one year, it will probably happen another. Having a plan and carrying it out is important to limiting deer damage, but what will discourage deer will also work on rabbits and woodchucks. These ideas could be called a “three-fer” by discouraging other mammal munchers at the same time.

Fact: Use deer or animal repellants regularly on plants during the growing season. Begin applying early in the season when the tulip flower buds are beginning to emerge and hosta leaves are just in the bullet, or rolled up, stage. In the spring, apply twice a week and repeat after a rain, especially if it is more than 0.5 inches. It’s the same deer that are frequenting your yard. Start training them early. Deer are not going to ride the bus to your yard from another area. By late summer or fall, you may be able to reduce your repellent applications to one a week or maybe less. You can purchase repellants or look to the Internet for some mix-your-own recipes to try. By using repellants during the growing season, deer become programmed to stay away from the stinky yard. They are less likely to change their habits in the winter.

Fantasy: You only need to apply a repellant once a month for good results. You have to consider yourself an animal trainer and be consistent in your message of “don’t eat here.”

Fact: Add or replace some plants in your landscape with some that are considered deer-resistant. Many of these have very distinctive odors. The reason is to give you fewer plants to protect from the hungry horde. 

Fantasy: Planting deer-resistant plants in your landscape will protect the ones that are being eaten. Planting deer-resistant plants does not stop deer from sorting through the rest of the garden for a tasty treat. They just avoid eating the smelly ones.

Fact: Give deer as few reasons as possible to visit your yard. This might involve using fences in the winter. See “Deer damage to woody ornamentals” for more information.

Fantasy: Feeding deer in the winter will give them “good” things to eat instead of your landscape plants. Many well-meaning people have created problems by feeding deer cracked or whole corn. This leads to a too common problem called corn toxicity. This can cause acidosis where the influx of high carbohydrate, low fiber, readily digestible food goes into the deer’s system that is calibrated for high fiber, woody browse plants. The pH drops in the deer’s rumen and gut activity stops and the animal suffers from indigestion, dehydration, diarrhea and eventual death. The other problem is entrotoxemia which is an overeating disease. This can also cause the rapid death of animals in relatively good condition. Deer will also show up for any material they can get out of bird feeders or off the ground.

Fact: Using a fertilizer like Milorganite may help discourage deer. Some gardeners have found Milorganite fertilizer to be a useful tool in repelling deer. The product says it has up to five-week repellency. Other possible aids include hanging chunks of strongly scented deodorant soaps in mesh nets, sprinkling human hair on the ground from a barber shop, scattering blood meal, and getting rid of outdated spices and herbs like cinnamon, red pepper flakes, cloves and anything with a strong aroma.

Fantasy: Believing that any of the products will last the entire season or maybe a month. You have to consider that you are always on duty and are trying to think about deterring the invaders at the gate.

Any of these tips and techniques will have various amounts of success. It may be impossible in some cases to prevent damage completely. The number of deer in an area and available food will make results differ. In the winter, the longer there is continuous snow cover on the ground, the more desperate deer become. They can dig through a few inches, but if it is heavy, deer may be forced to venture to places they regularly don’t go. Think ahead to prevent deer damage; it’s so much easier than trying to repair it.