Beginners don't realize that they don't need to clobber every groundhog that shows up. The best strategy is to isolate the first one someplace out of the way and just leave him there indefinitely. Only one can be on your property at a time.
Plant about six units of a crop in an out-of-the-way place -- or move them there. When you start to harvest, a groundhog will show up. What people don't realize is that you can then move the affected crops out of the area of the groundhog's influence and get on with your life. You can move trees, too, but not grasses or wildflowers. If you try to clear those out you'll have to pay double the usual amount of energy, BUT a neighbor visiting your homestead can clear them as though the groundhog doesn't exist.
High level settlers fence off their groundhog and work around him permanently, sort of like a zoo or a prison.
Much the same thing works for snakes and bears. Foxes allegedly have to be clobbered immediately, but I've never actually seen one eat a chick; they just writhe around acting disreputable, so I think they can be treated the same way. Supposedly, if you put your geese and chickens near the borders of your property it'll take you fewer clobbers to do the job, because the varmints tend to head for the border, but I'm not sure about that.
Oh, you can move those annoying signposts, too.