MANHATTAN, Kan. -- Early each spring, deer have many new opportunities for browsing routes. They scout out the best sources of succulent new leaf growth – which they’ll return to again and again through the growing season.
“That’s your best chance with repellents -- to have a real impact by somehow making your plants unappealing. Deer will check out your site a couple of times. If the plants always smell or taste bad, or if your site remains scary or hard to reach, deer may avoid your property for the rest of the season. They tend to be creatures of habit,” said Charlie Lee, K-State Research and Extension wildlife specialist.
Unfortunately, deer also habitually cause more than $250 million in urban damage to home landscapes, commercial areas and civic parks every year. That’s more than two and one-half times the annual deer damage in agricultural crops, according to USDA’s National Wildlife Research Center.
Several factors make urban areas the bigger problem, Lee said.
“Local codes and zoning regulations usually prohibit the best deer controls, including both hunting and 10-feet-high, woven-wire fencing,” he said. “Besides, cities don’t have natural predators, such as the gray wolf, black bear and mountain lion. Coyotes typically do no more than bring down the occasional fawn.
“Loud, protective dogs can be a great deterrent, but they aren’t much help in residential areas, due to leash laws and nighttime noise restrictions. So, human population centers serve as deer refuges – full of carefully tended landscapes with all kinds of deer food options.”
Other deer deterrents are imperfect solutions, in part because deer can figure out when repeated scare tactics bring no physical harm. That’s why urban homeowners need to try a variety of approaches, changing when one loses effectiveness.
“To a degree, though, you’ve got to weigh how much time and money you’re willing to invest, to try to save vulnerable plants. You might decide you’d rather replace what you’ve got with more deer-resistant plants,” Lee said, introducing these deterrent options:
* Deer repellents -- available in most nurseries and garden supply stores, as well as in some farm supply stores. They may not be safe or labeled to use on fruit and vegetable crops. Rainfall usually washes them away. Even without rain, some don’t weather well.
Among the "smell" repellents, a strong rotten-egg odor probably works best, either applied near plants that need protection or in a border around an entire area. Among the “taste” repellents, the fungicide- and hot pepper-based tastes can work fairly well, if applied directly onto individual plants, up to about 6 feet from ground level (as far as white-tailed deer can typically reach to eat).
"I personally haven’t had consistent success with commercial repellents,” Lee said. “But, some may be more effective than others. And, homeowners have told me about instances of repellents’ working very well, especially if started while plants are still dormant and before deer have made a habit of consuming your plants.”
* Hanging deer repellents – sometimes available commercially (e.g., coyote urine containers), but traditionally homemade by drilling a hole in a cheap, smelly bar of soap and stringing twine or rope through the hole. Research with fruit trees found “soap on a rope” can be effective in some cases. The approach requires hanging a soap bar every few feet from a valuable tree or along an entire fence line.
“Again, however, nothing works with deer every time. I’ve read reports of deer actually eating the soap. Lee said.
* Stiff netting designed to protect fruit tree canopies and/or “tubes’ designed to protect trees’ emerging shoots. In practice, they’re much like the fencing, wraps and tubing used to protect tender trunk bark from antler rubbing. But, they can be difficult to install, and they may degrade in sunlight.
* “Baited” electric fencing. For home use, Lee recommends metal conductor-reinforced polyethylene fence netting at least 4 feet high and attached to fiberglass posts (perhaps with wood corner posts). The metal conductor strands carry the charge from the energizer.
He also recommends two rows of stainless steel-reinforced polyethylene tape, strung 6 and 18 inches above the top of the netting (i.e., 12 inches apart). These ribbon-rows will make the fence more visible and reduce the probability of jumping.
“Deer can easily clear a fence that high, so you have to ‘drape and bait’ it to attract their attention and lure them in close enough to get a little shock,” he said. “I prefer peanut butter for bait, smeared at intervals on the tapes and netting. But, you could try peanut oil, apple flavoring or something similar.”
* Motion-activated water-blaster – hooked to a garden hose and staked out where it probably will water the garden as it startles wildlife. Some brands may adjust for a small or narrow yard.
“This seems like such a good idea. And, evidently, it’s fairly effective at repelling rabbits and roaming housecats. Unfortunately, I’ve never heard of anybody’s successfully using one to repel deer,” Lee said.
* Propane cannons, whistle bombs, shellcrackers, sirens, fireworks and gunfire -- effective short-term "scare tactics," particularly in early spring. But, having to create such noises when deer are present can mean losing sleep, as well as violating local noise ordinances. Plus, deer quickly lose their fear of regular patterns –noise levels, exploder sites, firing sequences, etc.
“Even if you change things around every few days, you really can’t rely on noise tactics for an entire growing season,” the wildlife specialist said.
Lee’s publication to help rural landowners control deer’s cash-crop damage is available online at Deer Damage Control Options.