If you have horseshoe-shaped mounds of dirt on your lawn, chances are you have at least one pocket gopher burrowing in your yard. These rodents, which can grow up to 14 inches long, can destroy well-maintained lawns and turf as well as ornamental plant life. The only way to remove these pests for good is to kill them, which thankfully is a relatively simple and straightforward task. Your best bet is to use poisoned bait, which is available from hardware and garden stores.
Look for any horseshoe-shaped mounds of dirt on your lawn or turf to confirm that you have a pocket gopher in your yard. Moles will create volcano-shaped mounds, so make sure that you have correctly identified the offender as a pocket gopher so that you can kill it effectively.
Probe with a long stick areas about two feet away from the tunnel entrance mound to try and find the underground tunnel that the gopher uses to move around the garden. These tunnels can be hundreds of yards long and several feet deep, although they can be just a few inches below the ground. Once you have identified the tunnel, dig down with a shovel so that it is clearly visible and big enough to easily place the bait inside.
Place three or four bait of your poisoned bait balls in the tunnel at various points. Re-cover the tunnel.
Check after one week whether or not fresh tunnel entrances have appeared. If not, the gopher will likely have taken the bait and should be dead. For larger infestations, it may be necessary to repeat this exercise a few times to kill all the rodents. Gophers are solitary animals unless mating, so any damage you find in your garden would usually be caused by the same gopher.