By Molly Rettig
If deer treat your yard like a buffet—munching roses, gulping from your pond, and nibbling your hard-grown fruits and veggies—you’re probably at your wits’ end. But it is possible to get deer to pass on the potluck.
Colorado has more than 600,000 deer, many of which can be seen strolling Boulder County’s neighborhoods like they own the place (which, of course, they once did). But a habitable yard for deer invites more than just a trampled garden. “If deer hang out in your yard, you’re at risk of having mountain lions follow them in,” says Dave Sutherland, naturalist and education specialist for Boulder Open Space and Mountain Parks. Mountain lions have a diet rich in deer—and much sharper teeth.
You’ve probably heard the local protocol for deer-proofing a yard: repellents, fences and unpalatable plants. But what about a homemade terrace or a motion-activated sprinkler? Some Boulder County residents tried these methods to outwit deer and succeeded.
Your choice of “deer-terrent” should depend on your problem’s magnitude, Sutherland says. “If someone invested thousands of dollars creating the world’s finest tulip garden, they’re probably going to want to fence it,” he says. “If someone only planted one tulip, stinky deer repellent is fine, which is what I’ve done for years and years.” Odorous repellents include rotten-egg mixtures, hot-pepper sprays, urine-based liquids and blood-meal powder, all available at nurseries and garden centers. The downside of sprays and powders is that you must reapply them after heavy wind, rain or snow.
When do you graduate from repellents to heftier investments? “Finally, my wife wanted tulips so badly that I fenced the yard,” says Sutherland, noting that a solid or net-wiring fence should be about 7 feet tall to keep out deer. The more desirable the food, the burlier the fence should be.
Another way to protect plants is deer netting, a fine black mesh that you drape over or stretch around plants or trees. “They don’t like it, because it gets stuck in their nose and antlers,” says Sutherland, who tented his entire vegetable garden and raspberry plants in netting. The caveat: other wildlife can also get stuck. “One time we had a bird hit the window, get stunned, fall into the netting and get caught by the neighbor’s cat,” he says. (A true animal-loving naturalist, Sutherland rescued the bird.)
While tulips and roses are deer-candy, plants like daffodils, irises, lavender, larkspur and delphinium naturally deter deer. The animals prefer well-watered and fertilized plants, because they tend to have higher nutrient levels and taste more succulent. Native plants don’t need much supplemental water or fertilization, making them less delicious. Another benefit: “Natives grow in the worst soil in Boulder—and they’ll grow happily,” Sutherland says.
Joan Lieberman conducted her own potted-plant experiment when she built a home on Boulder’s open space boundary 15 years ago. When she moved into the house, Lieberman planted a row of euonymus, an evergreen shrub. “I came out the next morning and it was like they’d been mowed down,” Lieberman recalls. So she set out a pot holding a different sample plant every day to test foragers’ appetites. Based on that, she planted mostly prickly lavender and yew—a shade-loving shrub that’s poisonous to herbivores. Yew is known for keeping out evil spirits, too, Lieberman says, along with deer.
During her second summer at the new home, Lieberman landscaped the backyard into 7-foot terraces. “Deer don’t like to be in an area where they can’t leap,” she says. Terracing the yard’s steep slope also helped keep dirt out of the living room.
Deer love to drink from water features and fountains, but sprinklers can spook them. Sandy and Bill Ingalls added a motion-activated sprinkler to their Boulder garden two years ago after deer began snapping their apple saplings in half. They affixed sprinklers at opposite ends of the 20-by-30-foot garden, and lifted bird feeders out of the animals’ reach with pulleys. “I haven’t seen any deer in the yard since we did that, so it seems to be working,” Sandy says.
In plotting deer defenses, be careful about planting nonnatives that could grow into more of a nuisance than the deer. Myrtle spurge, for example, is a drought-tolerant perennial that’s invaded natural areas around Boulder and Fort Collins. While unpalatable to deer, it causes other ecological problems. “Nonnative species can find a niche in our ecosystem and disrupt the way the ecosystem functions, either by suppressing or competing with native vegetation,” says Adrian Card, who manages the Wildlife Masters program at Colorado State University Extension. Myrtle spurge was sold at local garden centers until “we realized it’s not the best choice, and now we’re trying to reel it back in,” he says. “There is lots of it in Boulder.”
Lieberman’s neighbor planted two or three nonnative goat shrew plants she purchased from a local store years ago to keep deer away. By the following spring, however, the pretty purple flowers had encroached down the hill toward Lieberman’s house. “We had no idea it was such a menace. Its roots are deeper than yucca, and it trellises over other plants and steals sunshine and water,” Lieberman says. “I can’t tell you the number of hours we’ve spent trying to get rid of it.”
While different deer-proof strategies suit different homes, no method is foolproof. “They have preferences,” Card says of deer. “However, a deer that’s hungry enough will eat pretty much anything.”
Boulder County’s website includes a full list of pretty native plants that discourage deer.
The Colorado State University Extension website provides tips for dealing with urban wildlife.