In most areas of the country, voles can be found roaming gardens, tunneling within the top 9 inches of soil to look for grubs and plants to snack on. Hostas, with their thick, fleshy roots, are a favorite. Stymie these garden invaders with a physical barrier, like the modified 10-inch-diameter coated-wire-mesh wastepaper basket shown below. An inexpensive basket like this one protects all but the biggest hostas, for which you can craft a custom basket from hardware cloth. With the rim sitting just above the soil, the mesh protects the root ball while giving the roots room to grow. Once a vole bumps into the mesh, it will go around the basket, as it would a rock or tree root.
Here's how to modify a mesh basket like the one shown:
Mark a line 10 inches down from the rim of the container; make a crease along this line by pressing the wire out with one hand inside the basket while pressing the bottom of the basket with the other hand.