We had deep snow cover in the winter of 2011, and I had terrible losses of my perennials and bulbs to voles, and a bit of damage to shrubs. This was mostly in the front garden where the cat doesn't hunt. The carnage continued the following spring. I was desperate, tried a mole trap, encircling the roots of some perennials with hardware cloth, but with limited success. Finally I tried a castor oil solution recommended in the Hosta forum - and the vole damage stopped immediately! It was a miracle.

Now I sprinkle a castor oil solution around the root zones of many perennials and a few woody plants every fall. It lasts for months. I have an old watering can dedicated to this, because the castor oil is very sticky. Very little vole damage since using this solution.

We had deep snow cover again this winter, so we'll see. I suspect there may be losses where I didn't sprinkle the solution.

Sorry that your trees and shrubs suffered damage from the voles, ilovemytrees, but glad to hear that the fencing solution worked for you. I suspect voles of killing some of my seedling trees also. I think I will try the castor oil cure on the new trees I'll be planting this spring. Do you mix the castor oil with something or just pour it on straight, terrene? I have far too many trees over too much acreage to bury fencing, but I could maybe do the castor oil thing.

I have both voles and moles, but moles eat insects and worms, so I think it is the vegetarian voles that like to dine on young tree roots that are the culprits. They never seem to damage my perennials though.

Hi Spedigrees, the mixture is 1 TBSP castor oil and 1 cup human urine per gallon of water. Not really sure what repellent effect the urine has, and it could be optional, but it's good fertilizer anyway. Apparently the taste (texture? smell?) of the castor oil is repugnant to the voles, and it lasts for months in the soil. The castor oil does not appear to affect growth of the plants in any way.

You need to agitate the mixture well and sprinkle around the root zone. I use the old 2 1/2 gallon watering can, because it coats the inside of the can, although it does eventually rinse off. There is such a thing as "horticultural castor oil", but I've used CVS and Home health brands with good results.

Thanks Terrene! I will try it! Is there a reason why fall seems to be the season for treating/protecting trees? Is autumn when the voles plan their end-of-season banquet? Just wondering if small trees need protection in spring and summer as well, since I have a large order in for seedlings that will arrive shortly.

Hi sped, I think the solution could be used any time of the year that voles are active on your property. It lasts several months, depending on how much precipitation washes it through the soil.

I seem to get have the most vole activity during the winter, under the snow, especially when we get deep snow. Apparently there is a "subnivean" layer under the snow where the little rodents and squirrels tunnel around and do their rodent stuff. The snow insulates the ground and keeps it much warmer under there than the ambient temperature and they're mostly protected from predators. This winter I watched the squirrels pop up from the deep fluffy snow in the bird feeding area to snatch some seeds!

During the rest of the year, the cat catches a bunch of voles, and other predators do too, so that probably cuts down on their activity, at least for me.