published: January 2019

Garden Guru: Those four-footed rodents

by Matie Belle Lakish

Readers may have noticed my focus on wildlife in the last two articles. This month I want to highlight those four-legged visitors that gardeners usually consider less benevolent visitors to our gardens. Let’s start with the small ones—mice.

Because mice are low on the mammal food chain, they reproduce amazingly fast. A female mouse is sexually mature at 6 to 8 weeks, and each female can have 6 to 8 litters a year, with litters averaging 6 to 8 babies. Mice are likely to live and nest outdoors during the summer, and are not usually serious threats to gardeners’ crops, but they move into houses, greenhouses and sheds during the winter where they will eat young plants. They can wreak havoc on seed supplies and gardening equipment such as gloves. They also carry Hantavirus, a sometimes-fatal disease which has shown up in the valley in recent years. Outdoors, they will sometimes girdle small fruit trees by eating the bark all around the tree.

I find traps the best solution for mice. If you choose a live trap, please do not release the mice anywhere close to other structures. Some live traps, such as glue traps, leave mice maimed, so I prefer the quick death of a snap trap. Peanut butter is a good bait.

Voles, sometimes called field mice, are a related species of rodent with a shorter tail and ears, but in other ways quite similar to mice. They are more likely to live outdoors and cause problems for perennials and fruit trees in winter, and eat young plants in spring and summer. They will often dig shallow burrows and runways that are just under the grass or other plant debris, and will tunnel under snow in winter and sometimes girdle young trees and eat young tree roots. They do not make mounds.

If you see mounds of fresh earth in the vicinity of your garden, the invader is likely a Northern Pocket Gopher. Those dirt mounds are part of an extensive underground colony. I had an invasion of these creatures in my young orchard. They seemed particularly fond of my apricot tree roots, and the trees wilted and appeared stressed. I dug around and uncovered an extensive tunnel system leading under my garden fence, with new connecting hills of dirt about 10 feet away.

While an internet search reveals that poisons are largely ineffective, I would never consider poison anyway. Even if gophers ate it, which apparently they don’t, the other creatures who ate the gophers would die as well. Poisons are almost universally a bad choice, in my opinion. Among traps, the Victor Easy Set seems to be the preferred model.

I found an underground sonic device to be effective in my situation. Called a Sonic Mole Chaser, it emits an intermittent buzzing sound underground that is reported to drive gophers crazy so that they leave the area. In my case it worked. I purchased it through Jung’s Seed Catalog (jungseed.com) and the box identified it as a product of P3 International. If you stand close to it you can hear the sound it makes, but it was not bothersome in my orchard. There are several types of sonic mole chasers on the market, with varying reviews.

While I haven’t tried it yet, Jung’s catalog offers another type of Mole Chaser. It has windmill-like blades, and is attached to a long metal pole buried in the ground. The action of wind spinning the blades sends a vibration that drives rodents away. I have wondered if decorative wind-spinners would be as effective. If you have one, give it a try.

Rock Squirrels are a species that moved up from the south in the early 2000s. These large gray squirrels have meager tails, and prefer holes in the ground to trees. Rock Squirrels will mow down your young lettuces, broccolis, and other spring greens.  I once had a nest of them under the foundation of a house, and they made their way into the walls and attic. My dog was diligent about rooting them out, but it took her several months.

Fences, of course, are useless against squirrels. Try spraying young plants with a solution made by blending garlic, cayenne pepper and some soap flakes (not detergent) in water. Floating row cover may protect young plants when they are most vulnerable. Anchor it down around the edges with rocks or boards.

Rabbits, like squirrels, love young greens, but they’ll also eat more mature ones. Good fencing is the best preventative. You may need to add one-inch poultry netting around the bottom to keep out rabbits, or try the above spray on young plants. Rabbits will also girdle young trees, especially in winter when there is snow on the ground. Flexible plastic tree guards that encircle the trunk will help protect young trees.

Dogs and cats can be a deterrent. Most cats, however, won’t go after rabbits, and Rock Squirrels may be too much for them. The breed of your dog can influence his interest in protecting your space. My dog has some beagle, which makes her ideal for chasing rabbits. Shepherds may be more likely to herd you than to chase a squirrel. Most of us don’t pick our pets to protect our gardens, though, so we just have to love them as they are.