There are five species of gophers, or "pocket gophers" as they are more correctly called, that occur in California, however the most likely to be encountered in Los Angeles County is the Valley or Botta's pocket gopher (Thomomys bottae ). Pocket gophers are a small rodent about 5 to 7 inches long not including the tail. They come in a variety of colors but are most often greyish brown to brown. They have a very short tail, tiny ears and eyes, and huge, yellowish front teeth (incisors) which are always exposed. They also have large, curved front claws used for digging.
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How Do I Know if I Have Gophers?
Since gophers spend most of their time underground, they are hardly ever seen so the best identification method is to examine the dirt mounds that almost always accompany their activity. As they dig their tunnels, pocket gophers periodically shove dirt out to the surface forming mounds. The dirt is pushed to the surface from tunnels that are at an angle to the surface, so the mounds form in a crescent or horseshoe shape. This helps distinguish them from mounds made by moles which are volcano shaped. Pocket gopher burrows are almost always plugged. This helps to distinguish them from other burrowing rodents like ground squirrels or meadow mice. On average, a gopher makes about 1 to 3 mounds per day

Damage
Although gophers can be serious agricultural pests, in Los Angeles County most of the damage they cause is to landscaping and turf. They feed on many varieties of ornamental plants, and the mounds they make can be unsightly, damaging to turf, and even pose a quite real trip hazard on athletic fields.

Control
The most effective control methods for gophers are trapping, poison baits and burrow fumigants. Trapping and baiting are options that an ordinary property owner can use successfully. Burrow fumigants can be very effective but are restricted materials, generally only available to and used by professionals. Burrow fumigants are not the same as the commonly available "smoke bombs" which are not very effective. It is illegal in California to use carbon monoxide from car exhaust or other sources to kill animals.

Traps and poison baits can be purchased at almost any hardware store or home garden center and usually come with fairly complete instructions for their use. The key to successfully using traps or baits is accurate location of the main tunnel. Most people find it "by feel" using some sort of homemade tool or probe. Remember, poison baits can pose a risk to pets and wildlife if used improperly-FOLLOW THE INSTRUCTIONS VERY CAREFULLY. Homemade concoctions used to kill gophers or any other mammal are potentially dangerous and probably illegal. Don't use them!

What about flooding?
Outside of agricultural settings where a large amount of water can be put on an area in a short period of time and left standing for an extended period of time, this control method has very little practical value for residential uses. The old "garden hose down the hole" method tried by almost everyone who has ever attempted to control gophers rarely works and is usually a waste of water and time.

There are no repellents or scaring devices available at the present time that have been proven to protect lawns or other planting sites from pocket gophers. Several plants, such as gopher purge (Euphorbia lathyrus) and castor bean ( Ricinus communis), have been purported to offer protection from ravenous gophers, but these claims have never been proven.

Trying to keep gophers out of your yard or garden by using physical barriers can sometimes be effective if done on a small scale. Any large project, such as placing fencing around the perimeter of your backyard would be cost prohibitive and would at best only provide short term control. Raised flower beds can be protected by placing a layer of 1/4 inch galvanized hardware cloth under the bed and securing it to the 2x6 wood frame before filling with soil. In reforestation or orchard situations, a "cage" of hardware cloth lining the hole and extending six inches aboveground can give a young tree room to establish a good root system before being exposed to gopher damage.

Six to eight inches of gravel 1 inch or more in diameter around underground utility cables or sprinkler lines may discourage gnawing by gophers.

Legal Status
Pocket gophers are classified by the California Department of Fish and Game as a nongame mammal. If they are causing damage, they are allowed to be taken using gopher traps and poison bait by the owner or tenant of the property or their employees. Any poison bait used must be registered for use in California.

More Information
For more detailed information on gopher control, contact the office of the Los Angeles County Agricultural Commissioner/Weights & Measures Department, Pest Management Division at (626) 575-5462 and request a copy of the PEST INFORMATION SERIES on Pocket Gophers. That document can also be down loaded in PDF format by clicking here.