Urban Gardening

Living With Urban Wildlife Pests

Judging from the messages in my e-mail box, urban gardens are under siege. Food crops are being decimated, flowers are being attacked from the roots to the buds, shrubs are being chewed, and even containers are being damaged. City dwellers are learning that gardens are not only attractive to neighbors, they're also magnets for wildlife.

Young, tender growth is most vulnerable to rabbit munching.
Young, tender growth is most vulnerable to rabbit munching.

As suburbs and exurbs (sparsely populated residential developments on the fringes of suburbia) continue to encroach on natural habitats, animals are being squeezed into new areas. Although restoration and conservation efforts are beginning to stem the loss of wild lands, on the local level many animals simply don't have any natural habitat left. Fortunately, few species are actually endangered; many have been able to make a living right under our noses.

In fact, some animals do extremely well in human environments. The lack of predators combined with the bounty of gardens and garbage has been a boon for rabbits, squirrels, woodchucks, raccoons, skunks, and opossums. Unlike large predators, which we relentlessly eliminate (like the wild cougar recently found wandering the Roscoe Village neighborhood of Chicago), we generally accept the presence of herbivores of all sizes. Many people enjoy seeing Bugs Bunny or Secret Squirrel outside their windows.

But for gardeners such a scene may not be so serene. These critters can completely ruin an ornamental garden and spoil crops. How do we coexist with them and protect our plants? Here are some strategies for dealing with the most common culprits.

Rabbits

In the absence of predators such as coyotes, hawks, and bobcats, rabbit populations have soared. They thrive in cities as long as they have access to grass, with the occasional garden to nibble for variety.

This is the animal that frustrates me the most. Before I started gardening, rabbits were cute. Now I think of them as repulsive, hopping, mangy sets of jaws. One rabbit I could accept, but they really do multiply quickly. A family that moves into your yard will sample everything. They attack some of my favorites -- lilies, crocuses, asters, hepaticas, sedges, and tulips. Most vegetable crops are on their menu, too, although they prefer beans, peas, and lettuces.

In an ornamental garden rabbits do their worst damage in winter, when forage is scarce. Then they resort to eating the crowns of perennials and the buds and bark of woody plants. Woodies with thick and peeling bark are generally safe from rabbits, which seem to prefer plants with smooth, thin bark. They are also capable of killing small shrubs (young blueberries and azaleas, in particular) by chewing them to the ground. Snow cover protects them as they access stem tips and work their way down.

Deer

Because of their size, deer are more of a suburban pest, but they occasionally venture into city gardens to feed. If you live near railroad tracks, rivers, forest preserves, or other urban corridors, you're more likely to encounter deer. A lack of large predators and reduced hunting has led to overpopulation throughout North America. Having depleted their forage in the surrounding natural areas, these typically shy animals are forced into human environments for food.

If a tall fence isn't an option, try multiple repellents against deer.
If a tall fence isn't an option, try multiple repellents against deer.

A herd of starving deer will eat just about anything. They're especially good at removing the ornamental aspects from a garden. They target lily buds just as they are about to open, pluck tulip flowers one by one, and completely ruin shrubs and hedges. In time deer will create a browse line, where they repeatedly eat all greenery within easy reach -- between 6 inches and 5 feet above the ground.

A rare visit from a deer can be exhilarating, but frequent stops can be maddening. Fortunately, deer don't like enclosed spaces and are fearful of new experiences. If they were as bold and as common as rabbits or squirrels, urban gardens would be in trouble.

The Rodent Hordes

Rodents -- woodchucks (groundhogs), gophers, squirrels, chipmunks, mice, and voles -- are a major problem everywhere. This gnawing, burrowing family has learned to live with man — literally. Attics, crawl spaces, basements, and garages are fair shelter for some species, while others are content to move into our gardens and make themselves at home feasting on fruits, vegetables, seeds, and bulbs.

Voles, gophers, and woodchucks do their worst damage underground, eating established plantings of lilies, tulips, crocuses, trilliums, and other bulbous plants without the gardener ever seeing the culprits. But they will also venture aboveground to sample leaves and fruits. Every year voles ruin many of my tomatoes with their annoying habit of taking a couple of bites from one fruit before moving to the next. Near the parliamentary buildings in Ottawa, Canada, I watched woodchucks bite through sturdy plant stems and contentedly munch leaves only 10 yards from pedestrians on the sidewalk!

Woodchuck burrows can be hard to plug because they have more than one entrance.
Woodchuck burrows can be hard to plug because they have more than one entrance.

Squirrels are one of the worst rodent pests of urban gardens. They dig into beds and containers searching for edible bulbs, crowns, and seeds. This can be a double whammy because in their search they may toss plants out of the soil and leave them to die. Perched above for a bird's eye view, they're always surveying the garden. Every fall I can see them watching as I plant bulbs. As soon as I leave, they come down and examine what I've planted.

Their climbing ability gives them access to balconies, terraces, and roof decks that are usually safe from other pests. I have even had them break through my window screen to sample houseplants and steal nuts! In 1998 I awoke to noise coming from the living room. I staggered in to see a squirrel on the coffee table in the bowl of pecans. At 7 o'clock in the morning a squirrel on the coffee table looks as big as a bear. We both screamed. As he dashed out, he broke a ceramic pot on the windowsill. That day, I replaced the screen he had torn with a much stronger mesh.

This spring my sister and her family had a squirrel nest on their balcony. The mother squirrel had moved in between the decking boards and claimed the whole balcony as her turf. Anyone who stepped on the balcony was chastised and threatened. I laughed as my sister complained about the hostile takeover. (It's always hilarious when it's somebody else's problem.) Eventually the mother squirrel took the babies out for a climb and my sister quickly plugged the hole with steel wool. The squirrel family now lives in another balcony. These cunning rodents can be a handful, but they seldom do significant damage to the garden.

Racoons, Skunks, and Opossums

These animals are opportunists. They typically don't eat plants but gardens provide them with great habitat. Skunks and opossums can actually help gardeners by eating grubs, bugs, mice, and rats. Unfortunately, they dig up the lawn and garden to reach their prey. Both can take up residence in your yard, though a skunk is obviously the less welcome tenant.

Baffles on the trunks of fruit trees can prevent raccoons from reaching the goods.
Baffles on the trunks of fruit trees can prevent raccoons from reaching the goods.

Recently, a Chicago-area family had to move out of their home, remove their front porch, discard their furniture and appliances, tear down the drywall, and completely remodel when a skunk burrowed under the porch and released his scent near the ventilation system. It cost them thousands of dollars and incalculable frustrations because a skunk liked their yard.

Like some rodents, raccoons don't limit their territory to the outdoors. These masked marauders make homes in attics, basements, garages, and sheds, although they prefer hollow tree trunks. No garbage can is safe from the nimble fingers and quick minds of these voracious omnivores. While raccoons don't bother many plants, sometimes they'll eat ripening crops. They consider corn a delicacy and will wait until the ears are just ripe before raiding your patch.

(This trio of feisty, scrappy animals is known to carry diseases; do not try to handle them yourself. Call an animal control officer to remove them to avoid being bitten or sprayed.)

Fencing and Barriers

A fence is probably the best control option because it is preventative. Choose attractive fencing. For deer, fencing should be at least 6 feet tall and preferably opaque. Except for smaller rodents and climbing squirrels, standard chicken wire makes a suitable barrier against varmints. Fencing should be buried at least 6 inches in the ground to keep rabbits, woodchucks, and other diggers from tunneling beneath to gain entry.

Another option for preventing digging by squirrels and voles is to anchor wire fencing on top of the soil or containers and cover it with mulch. Half-inch mesh is small enough to deter digging and wide enough to allow most plants to grow. Mesh should extend beyond the planted area; otherwise rodents will simply dig around it to reach bulbs and roots. For the best prevention against diggers, enclose bulbs and plant roots in wire mesh baskets at planting time, or plant in raised beds lined with the mesh.

Repellents

Of the wide variety of repellents available, most are designed to simply discourage feeding so critters will go elsewhere. Depending on the product, you might dust or spray it onto plants, place it along the garden's perimeter, or place it inside holes or burrows. Common active ingredients include the urine of predators (e.g., coyote, fox), neem oil, garlic, and hot pepper. Most require periodic reapplication, especially after heavy rainfall. Follow label directions carefully for best results.

Motion sensor-triggered repellents are also effective. They use light, noise, and/or water to frighten wildlife away. According to Karen Schindelhauer of Con-Tech, "The ScareCrow motion-activated sprinkler automatically detects deer, raccoons, herons, dogs, and more as they approach, and repels them with a short but startling burst of water."

When I asked her about smaller mammals, she assured me that it works on them, too. A gardener had recently written the company to share his success story of repelling rabbits with the ScareCrow. If it works on rabbits, then it should ward off everything but small and burrowing rodents.

With the lines between wilderness and civilization becoming blurred, our urban green spaces are open to all types of animal visitors. Our gardens are viewed as both sanctuaries and restaurants, featuring comfortable quarters and fine menus. When we attract songbirds, hummingbirds, and butterflies, this is a benefit. But there are many creatures we may wish to outsmart. Now, if a bear wants something from your garden, I recommend going inside and letting him have it, with a smile on your face!


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