by Michael Davie, OCNT • Garden Manager
Being in the natural world, the landscapes we create and enjoy can come under attack by many outside forces. Too much rain, drought, freezing temperatures, diseases, infestations etc. One of the most prolific of these outside forces that effect our landscapes are animals. Of these animals we find that deer are some of the biggest culprits.
Controlling deer has become more difficult over the past few years. Due to continued construction—both commercial and residential—they have become more aggressive eaters due to losing their natural habitats. Deer populations in many neighborhoods have grown exponentially due to urban sprawl. Deer are (or were) very selective eaters that feed on leaves from flowers, shrubs and ornamental trees. However, since they are being forced out of their natural habitats, combined with drought like conditions over the past several summers, they are beginning to eat plants that they would normally avoid (oakleaf hydrangea, ferns etc.).
If you are noticing damage in your landscape, there are several ways to identify if it is indeed caused by deer activity.
Droppings: The first sign that you have had deer visiting are by scattered droppings. The poop is pellet-like (similar to a rabbits), dark brown to black and is usually in larger quantities.
Browsing (Eating/Tasting): Browsing can be neat or ragged depending on how strongly they pull at the leaves or branches. Like cows, deer are cud chewing animals so they rip and tear at plant material as opposed to biting and chewing. This type of damage is very noticeable.
Leaves are partially or completely eaten
Green shoots (new growth) chewed off trees and shrubs
Twigs ripped off branches (damage can occur up to 7 or 8 feet off the ground)
The severity of the browsing and plants affected depends upon the season and the severity of the weather patterns during that season.
Jan. – March: Conifers, evergreen needles and when desperate enough, turf
April -June: Herbaceous plants/ grasses, buds and shoots on trees and shrubs
July-August: Herbaceous vegetation, young leaves, annual flowers, anything in your home garden (hosta and day lily are a favorite of theirs)
Sept-Oct.: Fruits, vegetables from the garden, acorns, leaves from trees
Rubbing: In early fall, bucks rub their antlers on smaller trees to remove the velvet that has formed on their antlers through the summer months. This rubbing intensifies during the rut, which is the deer mating season.
Plant Selection: Use a plant that they do not typically like (with that said, remember if the conditions are right, they may try just about anything)
Placement: Place plants you love close to the house. In most cases they will avoid being near humans. Most plants are planted in the open yard and deer are opportunists so don’t plant the tasty treats where they can easily access them.
Companion Planting: Plant a border with strong smelling perennials in and around your favorite plants. Deer have a great sense of smell and typically don’t like things with a strong aroma. You can use plants such as lavender, thyme, sage, spearmint, marigolds, just to name a few.
Plant Texture: Make it uncomfortable for them by using plants that have unpleasant textures i.e., thorny (barberry), fuzzy (lamb’s ear), waxy (Wild ginger) or rough (brunnera).
Other ways you can use to deter deer from invading your landscape are through Repellents and Barriers:
Contact Repellents (sprays): These are typically concentrates comprised of blood or egg-based materials that possess a very off-putting scent (to say the least) and taste. Since they are sprayed directly onto the plant, they deer avoid eating them. The smell does eventually become undetectable to the humans, but with their heightened sense of smell and taste the deer can still sense it on the plants. If you have a larger herd of deer in your area, these applications will need to be made more frequently. Rain can have a negative affect on these types of deterrents.
Area Repellent (powder/granules): These repellents are usually comprised of a combination of ingredients (dried blood base or a mixture of concentrated spices that are offensive to the deer’s senses. These are typically applied around the border of the landscape to keep the deer from entering the beds. They also work great in planters. Depending on the product you are using, these can last quite a while and aren’t as susceptible to rain as it’s spray counterpart.
Caging, Wrapping and Netting: Depending on the type of plants you have in your landscape, placing wire metal mesh caging around trees and shrubs are a great way to prevent deer from reaching branches and leaves. They do typically need to be large (wide and tall) to do the job right. Wrapping a tree with a protective sleeve is another great option to keep bucks from rubbing their antlers on the trunk of a tree or shrub. Depending on the type of shrub or plant, netting is an amazingly effective barrier method for protection. This works great for taxus and specific types of hydrangea.
The most effective of all the methods mentioned here … is all of them. To be successful, you must use these methods in combination with one another. You have to continually mix up the types of spray you are using, along with the area control. Caging, wrapping and netting are paramount in this process as well. Timing on treatment is probably the most important aspect of good deer treatment program. In order to be successful, you have to be proactive and not reactive. There is no sure-fire answer to keep deer from invading your landscape so you have to try a little bit of everything and stay vigilant. Remember, if all else fails, just get yourself a big ol’ dog, that usually works too.