Hi Audrey - I can totally understand your problem with Voles! When I had them (which I hope
they aren't back this year) I thought I was done gardening - which I absolutely love. They almost destroyed my gardens and probably destroyed well over 75 of my perennials. My saving grace was finding the "Vole Control" website and ordering it. You really should check it out - I did - followed his instructions to the tee and fortunately took care of the problem. I had "12 Hot Spots" where there were dens and I was able to get rid of them.
Before I ordered "Vole Control" - I tried everything from smoking them out - traps - even calling in a critter control service and nothing worked. If you have a problem like I had - that's what I would suggest!
PS - My problem was so bad that I would lift my Hosta's right out of the ground because the roots were all gone.
Also - Voles live through the winter and continue to eat the roots of dormant plants - and continue to multiply! After they have a litter (usually at least 5) they will immediately get pregnant again - no waiting - so if you have them - they are almost impossible to get rid of.