Mole problem? Try trapping
Q: I moved from the Bay Area to the coast of Oregon. The weather patterns are similar, though a bit cooler and rainier, so your plant guides work well here. I still visit my mother in the Bay Area, and she handed me your article about gopher-discouraging plants. I was delighted that so many of the plants were protecting certain areas of our 1-acre property, but then suddenly realized that what we have aren’t gophers, but moles. We have a crazy mole problem in this area, and I’ve become a fairly good trapper, but I was wondering if you know whether the gopher plants would have the same effect on moles?
My vegetable garden is surrounded on three sides by escallonia shrubs and by our house on the fourth, and has only had one mole tunnel in two years. Similarly, a small area that I tamed with salvias and lavenders throughout is seeing little activity. Our open field is a disaster. Is it possible that the plants listed in your article will help?
By the way, I use the black box to trap moles, with great success. My tricks: I wear gloves when handling the traps (or they catch my scent, causing them to stuff the box with dirt), and I leave a freshly killed slug under the trap when setting it. Works like a charm. A: People with gopher-damaged gardens certainly wish there were plants so repellent to gophers that the voracious plant-eating rodents would stay 10 feet away from them. Unfortunately, there are not. The list I provided in my May 27 column (bit.ly/ Slq3y2) is only of plants that gophers usually don’t eat. And the emphasis is on “usually” because a hungry gopher may eat any but the most toxic plants.
I don’t know why some areas of your garden haven’t been interesting to the moles, but it isn’t what you are growing. Moles are not repelled by particular plants any more than are gophers. Indeed, being mainly carnivores, they have little interest in plants, their burrowing being, instead, a hunt for insect grubs and worms. (And I guess they must eat slugs, since they’re attracted to the dead slug you leave under the trap.)
Not plant eaters
While moles rarely if ever eat any kind of plant, they do often harm plants when their tunnels damage roots or dislodge flower bulbs. Moles also sometimes get blamed for damage caused by various kinds of mice, including the ones known as meadow mice or voles. Moles may be indirectly responsible, since their tunnels serve as ready-made passages for those plant-eating rodents.
Trapping remains the best method for dealing with moles in a garden. Results are faster if one sets several traps at the same time. There are several effective models, and gardeners may have a preference for one kind or be more successful at setting it. The black box type was designed for gophers, but is also sometimes used for moles. (Thanks for telling how you succeed with it!)
Slow tactic
Some gardeners try to rid themselves of moles by eliminating insects from the soil, but experts feel this is a slow tactic that may not prove effective. (And you wouldn’t want to eliminate earthworms, another favorite mole food, from your soil, because they help so much with fertility.)
Methods that have not been proved useful include vibrating or soundproducing gadgets and mole-repellent materials. Flooding or fumigating tunnels have also not been shown to have lasting success. Toxic baits are a poor idea because of the hazards to other wildlife and pets, and grain-based insecticides wouldn’t help in any case because moles won’t eat them.
Mole damage can be prevented with exclusion tactics used for gophers. That is, using special wire baskets under plants or lining the bottom and sides of planting beds with sheets of gopher wire.
Gophers or moles?
For those reading this who aren’t sure whether they have gophers or moles, you can tell which rodent you have if you find emergence mounds. Those of moles are circular, volcano-like, while those of gophers are more crescent-shaped. Moles also sometimes make linear disturbances of raised soil as they hunt in shallow tunnels, but they don’t always make these. (I’ve watched a plant tremble all the while it is being pulled slowly into the ground — a horrid sight indeed, and sure evidence that my problem was a gopher.)
For more information on gophers, moles and other vertebrate garden pests, see “Wildlife Pest Control around Gardens and Homes,” (Salmon, Whisson & Marsh, ANR Publication 21385) available at anrcatalog.uc davis.edu or at (800) 994-8849.