I don't know how it would work on groundhogs, but there's a product called Flaming Squirrels. It's a liquid Jalapeno pepper concentrate and it's advertised to keep the squirrels away from your bird feeders. You mix it with bird seed. It doesn't affect birds but squirrels do not like it. I had the big idea to put it in a spray bottle and spray our pomegranates. Squirrels have left the pomegranates alone, and that's amazing!! I wouldn't be surprised if it worked on your friendly groundhogs.. We put two tablespoons in a spray bottle & fill the bottle 2/3rds. Spray those squash and see what happens.. Beware, if I'm spraying the pomegranates, and the wind gets hold of the spray, my eyes and nose'll be watering and I'll be coughing too.. I'll take the chance for fresh pomegranate juice in a month or so.. A question though... does the spray penetrate into the fruit? I guess we'll find out.. The plastic bottle has a funny picture on the front.. A squirrel with flames coming out of it's mouth..