I always seem to have squirrels or chipmunks start digging in 1 or 2 planters each season. I usually put a few drops of peppermint essential oil on the potting mix in the planters they dig in and they stay away. Or I've held cotton pads in place using hairpins stuck in the soil and put the drops on the cotton pads, the scent seems to last longer that way.
I saw a squirrel trying to dig up my newly planted tulips last fall. I put a few drops of the oil on each hole I had dug and never saw them there again and didn't lose any tulips. I also use it under the hood of my car to keep them from nesting in the engine (and chewing wires) in the spring and fall.
It won't keep them from reproducing, but you might try peppermint oil where you want them to stay away. It works on many critters, even wasps. I dilute it with water in a spray bottle and spray where wasps like to go and they stay away. Put some dropperfuls around the plants you want them to stay away from, hopefully it'll work for you.
