Outsmarting Deer in the Landscape

By Gil Medeiros, Former Fairfax Master Gardener
Let’s be clear about one thing: Nothing works to dissuade deer 100 percent of the time except maybe a fence higher than 8 feet tall. Much has been written about deterring deer from the landscape, but the deer have read none of it. Let me channel my inner Abe Lincoln:

You can fool some of the deer all of the time and all of the deer some of the time, but you can’t fool all of the deer all of the time.

As a case in point, the deer problem in my neighborhood is not severe. We see one occasionally. Nevertheless, a Bambi look-alike walked past several yummy camellias and dined on my mayapple plants this past spring. Huh? Mayapples are supposed to be deer-resistant! I guess I should be thankful that the creature left my prized camellias alone.

Recently I attended an informative seminar on dealing with deer given by David Yost and Renatta Holt of Merrifield Garden Center in Fairfax, Va. Yost and Holt have extensive experience in supplying deer-resistant landscapes and deer deterrents to local residents, and they have learned over the years from customers what has worked well, worked a little bit, and worked not at all. While they were careful in the seminar to avoid creating an expectation that deer can be thwarted consistently, they did dispense useful insights about ways to reduce the probability of severe deer damage to your landscape.

Plant specialist David Yost discussed the dimensions of the problem. According to Yost, one deer consumes about a ton of plants per year. Some areas in Fairfax County have 40 to 100 deer per square mile. Do the arithmetic; that comes to 40 to 100 tons of hostas, arborvitaes, yews, camellias and other plants consumed annually per square mile in some unlucky parts of our region—a very heavy toll, indeed.

Deer are creatures of habit. Once they develop a taste for one plant in the landscape, they are likely to return to it, even as they bypass others of the same type. Efforts to deter deer from plants they have already enjoyed are likely to fail.

Perhaps, the most effective strategy for dealing with deer is using plants that the deer usually avoid. Landscape designer Renatta Holt said she prefers to design with woody plants rather than herbaceous perennials in neighborhoods where deer are a problem. Deer may not dine on the herbaceous perennials, she said, but the plants still risk being trampled.

Landscape designer Renatta Holt said she prefers to design with woody plants rather than herbaceous perennials in neighborhoods where deer are a problem. Deer may not dine on the herbaceous perennials, she said, but the plants still risk being trampled.

Here are Holt’s favorite deer-resistant plants:

Boxwood (Buxus spp). There are many varieties these days—some for sun, some for shade, with different colors and growth habits. Evidently, the distinctive smell of English boxwoods repels deer, but some Korean varieties with no noticeable odor to humans seem to work as well. Andromeda (Pieris japonica). They grow 3-5 feet tall and flower nicely in spring. Holly and holly look-alikes. American holly (Ilex opaca) and Dragon Lady (Ilex _aquipernyi ‘Dragon Lady®’) are the most reliable, according to Holt. Chinese holly (Ilex cornuta) with its very spiney leaves also works. Osmanthus (Osmanthus heterophyllus’ Goshiki’) is a popular holly look-alike that is deer-resistant. Cryptomeria japonica. It is also known as Japanese Cedar, although it is not related to true cedar. Make sure you have the right spot for this one because it can grow very tall. Thuja ‘Green Giant’ Arborvitae. Do not confuse this one with the narrow, columnar Thuja occidentalis ‘Emerald Green’ arborvitae commonly found in local landscapes; deer feast on those. The aptly-named ‘Green Giant’, however, can grow to 60 feet unbothered by deer. For that reason, it has become a popular landscape choice these days, but Yost suggested that deer might eventually develop an appetite for it, too. Juniper. Juniperus spp come in all shapes and sizes: ground covers, bushes and trees. Ornamental grasses. All kinds are reliably deer-resistant, including sedges. Deciduous ornamentals: Barberry (but rabbits like them), spirea, caryopteris, butterfly bushes, quince, and rose of Sharon (new hybrids do not self-seed)

Holt said that deer are not necessarily deterred by thorny leaves, but they are turned off by fuzzy leaves. In her experience, too, just because a landscape has been reliably resistant to deer for eight to 10 years does not mean deer will resist it permanently. She said she has seen landscapes that deer have ignored for years eventually devoured.

Yost discussed various strategies and products to repel deer. Liquid Fence, which has a very strong odor of rotten eggs, garlic and other scents, is the best-selling deterrent spray nationwide, and customers tell him it works well. Bobbex is the second most popular spray. A spray program that alternates Liquid Fence and Bobbex is considered the best approach to keep the deer at bay. Yost said the sprays do not have to be reapplied after rain, but they do lose their effectiveness after four to six weeks. Yost cautioned that failure to reapply is a major drawback to using sprays. If you choose this approach, put the next spray date on your calendar.

Dried blood, a byproduct of the meatpacking industry that is contained in little dispensers and hung from shrubs, works for a longer period than the sprays. Some of his customers like these dispensers, Yost said, but others have had no success. There is a systemic product called Repellex that is applied in tablet form to the ground under a plant. The plant draws it up through the roots, and the leaves and stems attain a flavor distasteful to deer for up to a year. This product is said to work fairly well but is the most expensive of the repellant options. There is anecdotal information, unconfirmed by science, that Natura Root Guard 8-8-8 Mycrotabs, a fertilizer product that contains mycorrhizal fungi, actually works as a systemic deer repellent. The manufacturer makes no such claims, nor have they registered the product with the U.S. Environmental Protection Agency as a pesticide. Still, Yost said, some of his customers claim that it works. Urban legend or fact? We do not know.

As for other options, lights, noise-makers and water sprays work for awhile until deer grow accustomed to them; then they don’t work at all, Yost said. Dogs are an effective deterrent, as long as the dogs do not lose interest in scaring away deer.

Yost said Rutgers University has the most extensive online listing of deer-resistant plants, and he refers to it frequently. Cooperative Extension publications on deer commonly reference it, too. See Landscape Plants Rated by Deer Resistance. However, if you look up mayapple, which the deer ate in my yard, you will find that Rutgers gives it an A-rating, the best for deer-resistance.

As I said at the outset, nothing works 100 percent of the time to dissuade deer.