Just saw this thread and maybe you have solved your vole problem, LeBug?
I had a terrible time with them this Spring, but now we seem to be vole-free thanks to a bait system(volecontrol.com). They ate all my 250+ tulips I planted in one long border last Fall, and then ate all the roots from a nice rosebush and a new tree. And I wanted to plant that area, which never seemed able to grow anything before.
Here it is now
