Problematic.

Every winter I seem to lose one plant to voles. One year, it was a large baptisia. At least it wasn't one of the hybrids I've been accumulating, and there were some babies nearby. So it wasn't a total loss.

That's what I was thinking. Thanks for the confirmation.

IME, voles will eat anything, specially succulent roots and any tender new growth

They seem to prefer bearded iris. Gaura was eaten in the first season it was planted also. They've been ignoring monarda, phyostegia, rudbeckia and verbena bonairensis. So far...

A nursery employee told me that voles hate hellebores because the root is stinky. She offered that idea without any prompting, so I'm not the only one around here with voles. I have half a dozen hellebores beside the house which have not been damaged but placing expensive plants at the back of the yard makes me nervous. Maybe I'll transplant hellebore seedlings back there.

The only hellebore with any kind of an unpleasant scent is Helleborus feotidus (aka stinking hellebore) and that is mostly wrt the foliage not the roots. ALL critters tend to avoid hellebores - deer, bunnies, gophers, voles - because they are poisonous in all their parts and taste nasty.

In ancient times hellebores were used as a poison by the Greeks to overcome their enemies.

I'm not so sure about any of this.

My sole success in getting deer to actually help in the garden is with hellebores. For several years in a row, they came and ate the old hellebore leaves - the ugly ones you are supposed to remove so the flowers can be seen. They did this for me.

Then there was the year the vole damage was the almost complete destruction of a hardy geranium. I think it was G. x cantabrigiensis. At the time, it looked like there was enough left that it would come back, but this spring the area seems full of violets.

For years now, I have been of the opinion that we need a concerted campaign to teach plants and animals to read. Life would be so much easier if they all knew what we were expecting of them, so they could at least pretend to play along.

I have found that a 6”-8” deep ring of metal 1/4” mesh (aka hardware cloth) or 1/2” plastic mesh buried with all but about 2” below soil level does a lot to preserve certain plants from vole predation. Depending on one’s particular vole species, they tend to live either at the soil surface or just below it, and having a physical barrier discourages them and redirects their tunneling in another direction. The fields that abut my gardens have hundreds if not thousands of voles, but I am able to grow clematis, Baptsia, etc. as long as I protect them.