You may have ground hogs if you see 10" — 12" holes on your property or your neighbors. You may have groundhogs on your property if you notice large bites taken from your vegetables garden fruits. You may have groundhogs on your property if you notice gnawed marks near the base of your fruit trees.
These are all symptoms of wood chuck activity. Wood chucks are also commonly called ground hogs. You may have noticed them along the highway as they sit on the rear haunches observing their territories. Once they decide that your home landscape is better suited to them than the open fields, you've got some serious problems you'll have to deal with.
Groundhogs hibernate in winter and don't usually stir from their comfy burrows. The same burrow is also used for mating (which occurs just after hibernation ends) and raising young. A groundhog burrow will often have one main entrance and an emergency escape hatch. Some groundhogs have a summer home and a winter retreat. Groundhogs are typically solitary critters, only getting together with other groundhogs to mate and for the mother to raise her young. Once the young have reached the age of consent, they get kicked out of the burrow to fend for themselves— seldom do they come home to do their laundry either.
When you have verified that you indeed have a groundhog on the property, you have a few courses of action:
Do nothing and enjoy watching the wildlife up close.
Scaring the groundhogs away from the garden with motion devices or making it uncomfortable for them to remain by using repellents either in the form of disagreeable odors or providing things that taste bad.
You can also erect fencing that will keep groundhogs out of the garden once you've removed the ones that you have living on the premises.
You can also place toxic gases into the groundhogs' burrows to help encourage them to take evasive action.
Option #2 is the most viable. Epsom salts can be sprinkled on the vegetation and fruits of your garden plants to render them foul-tasting to groundhogs. Epsom salts may even help some of your garden plants grow better. Rain will quickly wash away Epsom salts requiring you to make repeated applications which may not be quite as good for the plants as a single application.
Ammonia is also a deterrent. It is not only foul-smelling to the groundhogs, but to people as well. Ammonia-soaked rags can be strewn along the perimeter of your garden, forming a stinky barrier to repel groundhogs. But even ammonia's smell fades eventually and a re-application will be necessary.
Once the groundhog is removed, then fencing becomes the best way of keeping these guys away. Fencing will need to be 3' — 4' in height with a portion buried to help prevent tunneling. For extreme situations, you may even want to add an electrified hot wire that will give the animal a sudden, but non-fatal jolt when touched. This hot wire will need to be about 4" — 5" above ground level.
Groundhog control can be a long battle of wits between man and animal. It will take repeated attempts and combinations of deterrents for you to win.