Ann Wright: Gophers — Pests at the roots of a garden
July 13, 2018
The English language consists of so many words that have multiple meanings. For example, my 1964 edition of Webster's New World Dictionary has 10 definitions of the noun "root."
In the gardener's world, the root is an essential part of a plant, performing a number of functions to support the growing plant. In addition to anchoring the plant in the ground, the root system absorbs water and mineral nutrients, stores nutrients and carbohydrates and produces hormones to regulate plant growth.
Root of the problem
Recently a friend was dismayed when a favored rose shrub suddenly and very dramatically died. What caused it? Was it perhaps a hidden fungal or bacterial organism? What else was going on in the garden bed?
It seems there was a mound of soil piled adjacent to the rose. The rose dislodged from the soil fairly easily, and on closer inspection the root was clearly chewed — most likely, the cause was a pesky gopher dining on the roots. The remaining remnant of my friend's rose was a gnawed, lifeless root with dry, desiccated leaves and stems — quite dead.
As a source of food for natural predators such as snakes, coyotes, owls, cats and dogs, gophers are part of our ecosystem. However, natural predators rarely eliminate all the gophers — even one of these pests can destroy valuable gardens. So what can be done to protect roots from harm from pocket gophers?
Recommended Stories For You
The UC Davis IPM website offers an abundance of information about gophers and how to manage them.
To catch a gopher …
Gopher management is a complicated issue — one of the difficulties with gophers is that they remain underground in their burrows, and identifying the active burrows may take some practice. Is it a gopher or a mole? Gopher mounds are described as crescent shaped with tunnels over two inches in diameter as opposed to moles which mound dirt into more concentric round piles with burrows less than two inches in diameter.
Management of gophers essentially boils down to a few choices. One is to ignore them and hope they will go away. Another is to try to keep them out with fences using 1/2 to 3/4 gauge gopher wire or mesh hardware "cloth" buried at least two feet deep along the bed, and extending it about 12 inches above ground.
Raised beds can be built with wire mesh along the bottom, and wire gopher baskets can be purchased or made at home to protect individual plants. Galvanized wire provides the longest-lasting protection.
Traps are generally safe and effective (if handled properly). However, the use of traps is dependent on placing the traps in the gopher's main tunnel rather than lateral tunnels. Main tunnels in gopher runs can be somewhat difficult to locate.
With practice, a gopher probe can be used to locate the main run. On one side of a mound of fresh pushed up soil there will be a plugged opening to one side. Insert the probe about a foot away from the open side of the mound. A sudden drop will be felt when the probe enters the main run or tunnel.
Open the tunnel with a shovel and insert a trap in each run in opposite directions to make sure the gopher may be trapped if approached from either direction. The key to trapping is to be very persistent, check the traps every day, and set traps as soon as new activity is noticed.
If trapping or other methods fail, and the invasion of the gophers is intolerable, the use of toxic bait or poisons might be considered. If these methods are used, it's important to read all product labels carefully and follow the safety recommendations and directions to ensure the bait is not a secondary hazard to pets or children.
The effectiveness of commercial repellents and sonar or other devices to frighten gophers has not been established.
Help from the Masters
For more information about what is at the root of the problem with your plant, or for home gardening questions, call the Nevada County Master Gardener hotline at 530-273-0919, check the website at http://www.ncmg.ucanr.org, or visit a Master Gardener in person at the office at the Vet's Building, 255 South Auburn St. in Grass Valley, from 9 a.m. to noon on Tuesdays and Thursdays.
This is a good opportunity to bring in that dead root to have a Master Gardener help identify the cause of the damage. (Please bring all specimens in a closed, Ziploc bag.)
Master Gardeners are also available from 8 a.m. to noon every Saturday at the Grower's Market at the North Star House in Grass Valley. Also, the Master Gardeners will be at the upcoming Nevada County Fair.
Ann Wright is a Nevada County Master Gardener.