Those Vile Voles! by Louise Heern

These baskets have worked well for protecting plants from voles

Just when I think I can no longer tolerate the impossible growing conditions of high altitude gardening, I’ll catch an amazing view of the sun rising over clouds low enough to touch; a beautiful hawk soaring across a cerulean blue sky; or a cool breeze when the rest of Colorado is melting under hundred degree temperatures. There are so many beautiful advantages of high altitude living! So, I have decided to (finally) stop complaining! And, instead of fighting the gardening conditions here, I will work along with them.

First things first – the voles have to go!! If I were a cartoon character, (albeit sometimes I truly feel like one here) the villainous voles would be my arch-enemy. These destructive little creatures have transformed my once peaceful, ‘live and let live’ demeanor, into a ruthless, ‘spare no survivors’ vole hater. I have come to grips with the fact that, considering we live on a rock and dirt mountain-top, they will always be a problem; but after hours of research, trial and error, I have found some successful ways to at least keep their numbers under control in the areas I most want to protect.  

Sparing you most of the boring vole ‘facts’ here is what you need to know. Voles are small rodents that look like mice. They damage and kill plants, trees and shrubs by tunneling both above (meadow voles) and below ground (pine voles), eating the roots and gnawing the bark of trees. Voles do not hibernate and are active and breeding year round, reproducing three to six young per litter with three to 12 litters per year! (A gestation period of 20 to 23 days.) You do the math. If left unchecked, that can be a lot of voles!! They do lots of damage in winter under the protection of snow cover. Tell-tale signs (besides dead and/or missing plants) include several one to two inch diameter holes in the ground with or without mounds of freshly dug dirt piles nearby.    

Control measures are the same for both types of voles, however, pine voles are harder to control due to the fact they live underground. When we first discovered we had a vole problem, we started out like most folks leaving folded up pieces of Juicy Fruit gum in the holes and spraying castor oil around. (At one point, I was buying so much castor oil that I would purposely try to go to different checkers at the local Walmart, embarrassed that they were thinking I had a serious constipation problem!) We quickly learned neither one of these methods were working.

Finding the best method for your garden may require some experimentation as well, but here are some of the methods that have actually worked for us and other gardeners I have met along the way. I hope one will work for you!

We have personally trapped over a hundred voles these last couple of seasons using ordinary snap mouse traps baited with peanut butter. For the above ground voles, we place a baited trap only in the areas we have seen them, or signs of them (usually under a particular plant or close to the foundation). Cover the trap with an inverted bucket or flower pot heavy enough to withstand some wind. Use a flat rock to leave a small gap in-between the bucket and the ground for the vole to crawl under. (Covering the trap also protects non-target critters such as birds, etc.) The same peanut-butter baited snap trap works well for us when placed perpendicular to the runway of the underground holes with the trigger end in the runway. Again, be sure to place an inverted bucket or flower pot over the hole with a rock on the top to keep it in place. Be vigilant about checking and re-baiting the traps until signs of activity stop. If you have lots of holes, you can identify the active tunnels by smashing down the entrance with your foot. If the tunnel is rebuilt in a day or two, you will know that it is active. These active tunnels are where you will be most successful. Don’t forget to cover them and always use gloves when handling the traps.

As far as deterrents go, my personal recommendation is an eco-friendly, non-toxic product called Plantskydd. It comes in both concentrate and granular form and continues to work very well for us.  

This year I have planted any new perennials and rock garden plants in $1.00 wire baskets I have found at The Dollar Store. They come in two sizes (see picture below). The basket is deep enough to protect the main root crown of the plant but still lets the smaller, thinner roots grow through the sides and bottom. I left about an inch of the basket above the ground level and sprinkled the granular Plantskydd around the base of the plant. Stay tuned, but so far this is working great!!

For smaller areas you can purchase battery or solar devices that emit intermittent vibrations.

Protect young tree bases in winter with galvanized hardware cloth cylinders. Make a cylinder around the trunk and bury it 6 inches to prevent voles from burrowing under. 

I would be remiss if I did not mention things that may be attracting the voles to our gardens in the first place. I love to watch the birds at our feeders, but fallen birdseed from feeders attracts voles. Cleanup and prevention of birdseed falling to the ground will reduce vole infestations, especially in the winter! If you have vole problems in your vegetable garden, remove carrots and any other root crops that may provide a food source over winter. Also remove any refuse they may hide in.

Are you interested in learning more about gardening in Clear Creek County? Contact Chris Crouse at the CSU Extension Office christine.crouse@colostate.edu for information regarding our 2014 Master Gardener Program.