Q. How do I control moles? My yard is tunneled to death! And what's the difference between a mole and a vole?
---Joe in Alexandria, Virginia
Our neighborhood has been invaded by voles, which have destroyed my grass. What can I do?
---- Antoinette in Arlington, VA
A. In the past we've always explained that moles create raised tunnels and voles don't. That's still the case, but I've been doing more research, and it turns out that there are many different types of voles—and some of their behaviors can be radically different than the ones we've discussed in the past, including a type that does damage lawns.
But let's begin with a few things that haven't changed: Moles—M O L E S—live exclusively underground, make raised tunnels (mostly in lawns), often leave big piles of dirt on the surface, and eat ONLY live food: earthworms, beetle grubs and cicada larvae. They may uproot the occasional plant, but they don't eat any plants. Moles are the cause when a lawn has raised tunnels, dirt mounds and soft areas that collapse when you walk on them.
But if instead of (or in addition to) raised tunnels there are lots of little 'runways' about two inches wide throughout the lawn, the cause is a specific type of vole—V O L E—that eats grass blades and tramples down the area as it makes intricate above-ground pathways. The way to tell that it is not mole damage is by these distinctive chewed-down runways, lots of little holes about an inch and a half in diameter in the soil and the lack of dirt mounds.
Q. How can I rid my lawn and garden of voles? They've chewed the roots and stems of my shrubs and other plants and are destroying my well-tended lawn. I don't want to use poison as I have a Labrador retriever. I've tried coyote urine and other repellents and even stuffing their tunnels with Juicy Fruit gum, but they're still out there."
---- Jeannie in West Chester, PA
A. Voles are well known for eating the roots of plants, consuming Spring bulbs and tubers underground (other than daffodils, fritillaria, and garlic, which they avoid), and for chewing on the bark of trees and shrubs—especially over the winter. Mounding mulch over the base of trees invites this damage by providing protection from predators—but snow cover can hide the little rodents just as well. That's why new plantings should always have a six inch area of 'no-mulch' next to the stem and be protected by a wire cage or by wrapping the trunks with tree guards or hardware cloth—a type of small mesh metal fencing. All three forms of protection will also keep rabbits, groundhogs and deer from gnawing away.
And what about Juicy Fruit gum? There's something I hadn't heard mentioned in quite a few years, although 'the Juicy Fruit trick' has been around for decades! You generally hear it suggested for moles, which is just ridiculous, as moles are 100% carnivorous and only eat live food. I could maybe see a vole trying some out of curiosity, but I wouldn't rely on it for control.
But I would give castor oil a try. Whenever people start to see signs of mole and/or vole damage on their lawn, I always suggest they start out with a castor oil-based repellant labeled for use on moles and voles. It doesn't actually harm the creatures; it just chases them off by making the soil smell bad under the surface. For the best results, apply it heavily in the Spring—before the females begin mating. One female vole can easily give birth to a hundred tulip-eating offspring by the fall; their fecundity is legendary.
There isn't good evidence that predator urines work—and their 'collection' is cruel in the extreme. And poisons are to be avoided at all costs; they're a threat to children, pets, and the natural predators that can help keep these creatures under control--especially hawks and owls, which are big predators of voles.
True story: It was the beginning of Lent a few years back when my local church's front yard started showing signs of vole infestation—lots of inch and a half wide holes near bulb and shrub plantings. They asked me for advice, and I had them change the location of the big crucifix they traditionally put out during Lent so it was right in the middle of the holes. And they added a pair of smaller crosses for the Two Thieves. By the time Easter arrived, hawks and owls had clearly taken care of the voles—the area was covered with 'owl pellet evidence'. Raptor perches can be very effective; just a simple crossbeam about six feet off the ground right over the damaged areas.
Removing heavy mulches helps keep voles under control. (And remember—no mulch should ever TOUCH a tree or other plant!) But voles also like to hide under heavy ground covers, like pachysandra, ivy, and low-growing junipers. In situations like that, traps can help limit their numbers: Simple mouse or rat traps baited with peanut butter placed around or over their runways and holes. Cover the traps with heavy cardboard boxes with little cartoon 'mouse holes' cut out of the bottoms so voles can run in, but birds are kept out.
And keep in mind that the word 'vole' applies to a number of different creatures (which, to add to the confusion, are often referred to as meadow mice or field mice, despite the fact that they aren't mice!). Some voles mostly make above-ground runways; others make extensive tunnel systems and do most of their eating underground. The different types can look and behave very differently, and even researchers disagree about some very basic aspects of their behavior. The one thing they all have in common, however, is that they're nocturnal, breed rapidly, and can cause a lot of damage.
Here's a good article about the different types of voles and their ranges (just ignore the advice to use poison baits; they are not safe for you and other living things).