Audubon At Home
Each year doe-eyed marauders lay waste to America’s backyards, devouring everything from flowers to vegetables and saplings. Here’s how to protect your precious plants.
Karen Rohovsky has thought about giving up gardening. “I don’t know what else to do,” says the certified master gardener, who grows wildflowers, shrubs, and shade plants on her three-and-a-half-acre property in Solbury, Pennsylvania. The source of her frustration: long-legged bandits. “The deer have been devastating my plantings,” she says. Hostas are supposed to be large and bushy, but hers are puny stubs. “I put in a meadow of all native wildflowers,” she laments. “The deer love to make nests and hideouts in there. They smash everything down. It’s very frustrating.”
Rohovsky is not alone in her exasperation. Throughout the deer-crowded East and beyond, gardeners are complaining about doe-eyed marauders picking off their posies and vegetable plants. What’s more, deer are now foiling gardeners’ efforts to grow endangered and threatened native plants in backyard wildlife habitats. But with the right tools it’s possible for determined gardeners to keep deer from wiping out—sometimes even in a single night—years’ worth of watering, weeding, and expensive landscaping.
Deer have not always been garden pariahs (and to some wildlife-loving gardeners, they’re not). In fact, today’s omnipresent white-tailed deer had nearly vanished in the late 1800s in parts of its eastern range because of unregulated hunting. Since then the habitat it thrives in has increased as a result of both human prosperity and misfortune. Rapid development of formerly forested areas has created the grassy edges that deer particularly like, and so has the reversion of abandoned farm fields to forests. Meanwhile, the long-term absence of such traditional predators as mountain lions and gray wolves as well as restrictions on deer hunting in populated areas have removed the last checks on booming whitetail populations throughout the Northeast and in many midwestern and western states.
A lady slipper can take seven years to flower,” says Brad Roeller, manager of the display gardens at the Institute of Ecosystem Studies (IES) in Millbrook, New York, where white-tailed deer concentrations have reached record highs of up to 55 animals per square mile (compared with 7 to 10 deer per square mile prior to European settlement). “So when some deer comes up and takes that plant, it gets my attention.”
In the early 1990s he was approached by Paul Curtis, an associate professor in the Department of Natural Resources at Cornell University, to put into practice research that Curtis and others had done on deer-resistant, popular woody ornamentals. Roeller set up a deer browse garden at the IES facility using Curtis’s plants. There he would continue to evaluate deer resistance, measure plant damage, and analyze repellents and other products. On the very evening the garden was planted, he climbed into his camouflage gear, shimmied up a big oak tree, and waited to see if the deer would take his bait. “The first night I was sorely disappointed,” he remembers, slouching, his thumbs tucked into the back pockets of his jeans, in sight of the old oak. “One deer strolled through and sniffed around on its way to somewhere else. But by the fourth night I had 40 deer.”
Roeller’s late-night surveillance of the deer feasting on carefully selected plants confirmed earlier studies that showed these animals are not picky. “They browsed natives, exotics, yews, rhododendrons, American holly, conifers, blue hollies, ferns, mondo grass—you name it,” he says. By the end of that first spring, normally waist-high plants were nothing more than nubs. Anything that somehow managed to escape consumption over the next few years was assumed to be somewhat deer resistant and moved to another garden, where Roeller’s experiments continued.
He found deer to be very curious by nature—they tasted any new plant. And when they discovered a place they liked, they stayed. From his perch in the oak, Roeller regularly watched four generations of female deer grazing together: great-grandma, grandma, mom, and yearlings, which meant that information about the best foraging areas was always being passed along to the herd’s youngest members. He learned several simple truths: In times of drought, or when acorns (a key deer food) are scarce, all bets are off—“starving and stressed deer will eat almost anything”; the truly deer-resistant plants are few—“you can count them on two hands”; and “the words deer-proof are a farce.”
After a decade of tempting deer with a smorgasbord of plants, including a long list of perennials scattered throughout other parts of the IES gardens and his home landscape, Roeller compiled a record of those that deer, in general, don’t like (see “What You Can Do”). Among the plants that have made the cut are astilbe, with its feathery plumes and arching spires of flowers in shades of pink, crimson, purple, and white; royal fern, a shade lover whose ancestors have covered almost every corner of the earth; and bush cinquefoil, a deciduous shrub with blue-green foliage and summer flowers that come in a range of colors, depending on the cultivar.
Roeller has also tested, with varying degrees of success, a battery of commercial deer repellents marketed by companies like Leg Up Enterprises Inc., and some homemade remedies, too. Repellents contain such ingredients as hot peppers, predator urine, soap, eggs, dehydrated animal blood, and citrus oils, which overwhelm a deer’s strong senses of smell or taste. Roeller recommends spraying new plantings with an “odor-based” repellent, such as those that contain dried blood, urine, or eggs. If a deer’s first encounter with a plant is unpleasant, it will be more likely to skip that one on its next tour through the neighborhood.
To keep deer from becoming acclimated to a particular product, Roeller frequently switches the ones he’s using. His favorites include Hinder Deer and Rabbit Repellent; bars of soap (any kind will do) placed every three feet in small cages atop bamboo sticks; Liquid Fence; Bobbex; a Swedish product called Plantskydd; and a homemade recipe that was slipped to him years ago by an elderly woman who attended one of his talks on deer browsing. The basic ingredients in that recipe are a half-cup of whole milk whisked together with one egg and combined with a tablespoon each of cooking oil and lemon-scented dish detergent, diluted in one gallon of water. For a more potent brew, he spices it up with a couple of drops of rosemary oil and a dash or two of hot sauce. This mix should be applied to plant leaves with a spray bottle every 10 to 12 days, and in spring it can be combined with fish emulsion for fertilizer.
Over the years Roeller has evaluated a number of deer-deterring contraptions, like the one he refers to as “the clapper,” a device with two pieces of wood rigged to a timer that triggers the pieces to slap at certain intervals, startling approaching deer. (At least it scares them until they get used to it, which, in Roeller’s field tests, took about three weeks.) Once he even resorted to rock music activated by motion detectors. “We had AC/DC going off at two in the morning—the neighbors didn’t like that one very much.”
Other high-tech deterrents are becoming increasingly popular. This past summer Roeller had planned to try out an expensive ultrasonic system. That is until he saw test results of a similar product developed in Australia to keep kangaroos out of croplands. The kangaroo system was recently evaluated for its effectiveness on deer by Cornell’s Paul Curtis and Michael Fargione, educator for the Cornell Cooperative Extension of Ulster County, New York. They found the system failed to prevent deer from entering an orchard and feeding on the apple trees, even though the units were placed closer together than recommended by the manufacturer. Curtis has tested similar scare devices specifically targeting deer that haven’t worked very well either. Roeller’s not surprised. These scare devices remind him of his failed tests with rock music and the clapper, both of which likewise played on a deer’s detection of sound frequencies—which, it seems, are less important when it comes to deterrence than its senses of smell and taste.
There are preventive measures that play on a deer’s weaker senses, too. A simple tactic, one Roeller plans to experiment with more, is a “poor man’s fence,” which is based on his observation that deer are reluctant to leap over obstacles that have both depth and height. It’s made from two inexpensive and readily available materials: clothesline and fishing filament. Clothesline, strung around the garden at a height of 28 inches, provides the inner barrier. The outer barrier is made with fishing line pulled taut at the same height and set about five feet out from the clothesline. “The separation between the two fences makes deer uncomfortable to jump over both barriers, as they can’t clearly distinguish what they’ll land on,” says Roeller. “The monofilament throws deer for a loop because they can’t see it, but they feel it. I also reinforce this factor with odor-based strips of fabric on the inner fence.” For added insurance, he ties a couple of nylon flags, cut in the shape of a deer’s tail, to the fishing line, simulating the alarm response triggered by the flash of a fellow deer’s white tail.
Another alternative is so-called “invisible” fencing, like the kind distributed by Benner Gardens in Pennsylvania. “The deer can’t clearly distinguish the top of this 7.5-foot-tall, black PVC fence,” Roeller says, “and are therefore tentative to try to jump it.” In fact, tall fencing—invisible or otherwise—combined with a solid gate at the entrance (a fence’s “weakest link,” Roeller says) is widely considered to be the surest way to keep deer out of a garden. Just ask Marion Kyde. Five years ago Kyde, a mycologist (mushroom scientist), avid native plant gardener, and bird lover, decided to quit pouring thousands of dollars into woody and perennial plants only to see them get eaten by a herd of up to 35 deer that frequently wandered through her 30-acre woodland property in Ottsville, Pennsylvania. Instead, she and her husband, Neil, bought and installed a barely visible black plastic fence from a company called Deer Busters and stretched it themselves from tree to tree, enclosing roughly 10 acres around their house. They named the area Tulgey Wood after the enchanted forest filled with strange birds in Alice in Wonderland. The finishing touch for their fence was a $6,000, energy-efficient electric gate that opens automatically for cars as they drive over special sensors buried underground but secures the fortress when deer approach.
Conjuring the image of a modern, middle-aged Alice herself, Kyde is a petite, curly-haired woman who stands like a dancer, with her shoulders rolled back. On a sunny June day she meets a crowd of visitors in a short-sleeved sage sweater, flowing paisley skirt, and red sunglasses, and escorts them into her wood, declared a State Stewardship Forest 11 years ago. The towering canopy of old trees inside the fence shelters a thick understory of sugar maple, oak, ash, walnut, hackberry, and sassafras saplings, as well as viburnum and spicebush shrubs. But this forest hasn’t always looked so healthy. “This was absolutely bare,” says Kyde.
To illustrate her point she shuttles her guests outside the fence. There the tall, mature pines, oaks, and maples still stand, but the understory is a barren, parklike setting of thick tree trunks surrounded by a desert of stilt grass and garlic mustard. Well-worn deer paths hug the fence line. Kyde is employing another deer-management tactic on these 20 acres: hunting. She hosts two trusted woodsmen from October through January. It wasn’t an easy decision. “I hate hunting. I hate killing things. I don’t eat mammals,” says Kyde. “But there was nothing else to do.”
Responsible deer management is a measure that conservation biologists hope more gardeners will get behind. “All these things—deer repellents, fencing, deer-resistant plants—push deer into other areas,” says Bryon Shissler, a wildlife biologist with a Pennsylvania company called Natural Resource Consultants Inc. “They do nothing to resolve the larger issue [an exploding deer population]. If you have a real interest in biodiversity, you need to get together as a community and come up with a plan. In many cases, that must involve deer reduction. You have to somehow lower abundance of deer to reduce impacts on the habitats they occupy.” It’s a position that a number of conservation groups, including Audubon Pennsylvania, have embraced in recent years, in the face of some public opposition. “People ask, ‘Why does Audubon Pennsylvania care about this?’ ” says executive director Timothy Schaeffer. “What we care about is the habitat of birds and wildlife. When I first took this job, I was startled to find out that 17 percent of the world’s scarlet tanager population nests in Pennsylvania. Protecting that habitat is a globally significant stewardship responsibility.”
Kyde knows that by taking matters into her own hands and fencing 10 acres of bird and wildflower habitat she has pushed some deer onto the property of a neighbor—one whom she doesn’t particularly care for. “I feel about this much guilt about that,” she says, pinching her thumb and index finger.
Back inside the fence, she proudly points to clusters of low-growing plants with lily pad–size leaves. “This is my trillium garden,” she says, beaming. “We haven’t seen these for a while.... And here’s spicebush, an important food for migratory birds because of its high fat content. Without the fencing, you lose the viburnums, then the spicebush, and you’re left with autumn olive. If you’re a shrub-nesting bird, you’re hard pressed.” The deer, on the other hand, often appear to prevail. “The day after hunting season closed last year,” Kyde says, “we had 17 of them cross the driveway. Those little buggers.”
What You Can Do
It might sound counterintuitive, but development and habitat fragmentation are actually boosting deer populations in many places while at the same time negatively affecting other types of wildlife. Anyone who buys a home can help reduce those effects by opting for an already existing house in or near an urban area instead of building new in a forest or on its edge. The government plays an important role as well. Ask your state wildlife agency how it controls deer damage in your forests. For information on managing deer in ways that promote healthy ecosystems, log on to Audubon Pennsylvania’s website, or view Brad Roeller’s list of deer-resistant plants online. Additional lists are available at The New Jersey Agricultural Experiment Station website. For further reading, check out Deerproofing Your Yard & Garden, by Rhonda Massingham Hart. If you have effective home remedies, send an e-mail to firstname.lastname@example.org and then look for them on our website.