- Author: Jenni Dodini
Published on: September 9, 2021
So, you know exactly how it goes when you look at somebody else's garden and think to yourself, "Why isn't my garden blooming like that?" Well, that's what went through my mind when all the bulbs that I planted at my daughter's came up and flowered and the same types of bulbs that I planted at my place last year are nowhere to be seen. So, I went and REALLY looked at the area closely and found holes and loose soil where said plants should have been. The only plants remaining are the bearded iris and maybe the daffodils that bloomed in the spring.
After, yelling at the SUC's (Stupid Underground Creatures) for eating all of my hard work, I thought I had better do some research so that this doesn't drive me crazy again next year.
Now, mind you, most of my plants are in pots or raised gardens and the raised gardens that are on the ground were built on top of 1/2 inch square mesh. That happened after some SUC gnawed through the bottom of a plastic pot and enjoyed all the hosta tubers in said pot. For some reason, this particular area is not planted that way, and I think it was because of the size of the area.
Anyway, off to the Internet for information about said SUC's. I have seen both gophers and moles out here over the years, so I started with those two. I'm sure that there are probably voles underground too, but I can't actually say that I have seen one. The UCANR.IPM site has all kinds of information and really good pictures, so I would invite you to check it out if you find yourself dealing with SUC's. Also, there is a GREAT PowerPoint that gives a whole lot of information on the creatures as well as the study results on the various poisons, traps, and control methods: Cesonoma.ucanr.edu>files. I also looked at Smiths Pest Management site because they gave good instructions for things you can try first, then you can call them to come help.
Here's the short version of my hours of research:
There are six species of vole, Microtus, in California with Microtus californicus being the most widespread one in our area. They are mouse-like rodents and look similar to the pocket gopher. They can be seen above ground but stay mostly in their short, shallow burrow system. You can see their well-traveled runways between burrow openings which they cover with the surrounding vegetation. They are active 24/7 all year. They make underground nests and can breed at any time of the year, but mostly in the spring. The female matures in 30 to 45 days and can birth 5 to 10 litters/year, with 3-6 young/litter. The life span is about 12 months. The overall population varies from year to year but tends to peak every 3-6 years. Voles are indiscriminate herbivores and will eat pretty much anything from veggies to trees. Since they really don't climb, you would have to check your tree for gnaw marks from a few inches above to a few inches below the soil level if you suspect they are the cause of girdling damage. Once you suspect their presence, check areas that provide vegetative cover for trails and droppings and remove it, if possible. Monitor heavy mulch for ridges where they have traveled just under the surface. Manage weeds and keep a clear area around gardens as voles don't like to feed in the open. Barriers can be placed 6-10 inches below the ground surface but must be made to fully surround the area as the voles will just burrow around them. Trapping requires accurate placement and frequent checking and really only works when numbers are small. If you try trapping, be mindful that voles carry diseased parasites and pathogens and must be handled with gloves and disposed of in sealed plastic bags. Commercial repellents have questionable efficacy. Toxic baits MUST be used carefully and according to directions, keeping in mind that they can also poison the animals that feed on them. Fumigants simply don't work.
Contrary to common belief, moles are not rodents. Moles are members of the Scapanus species. They are anti-social creatures. Except when breeding, there is only one animal in a tunnel. They breed once a year, producing 3-4 young, usually in late winter to early spring. Their permanent tunnels are 8-12 inches below the ground. When making tunnels, they push the soil out of the tunnels in mounds and the soil looks clumpy. Molehills tend to be about 6 feet apart. Moles have 22 tentacle-like protrusions on their snout which are 6 times more sensitive to touch than the human hand. Their eyes are very poorly developed and the ears are not visible. Moles only eat earthworms and insects. They can eat up to their body weight in one day. The damage done to plants is caused by their burrowing which causes the plant's roots to dry out. They will burrow under a plant to get to the tasty morsels in the roots. If you see gnaw marks on a plant, it was not a mole. It has been found that no control method is 100% effective. Trapping is the most effective and dependable if done correctly, but it can be expensive. Toxic baits are still being tested. Mechanical repellents are said to work by irritating the animal, causing it to "move away." Moles don't like strong smells.
Gopher is the common name for the Thomomys species, of which there are five in California. The one that is common here is the pocket gopher, T. Botta, so named because of its pocket-like cheeks. The cheeks are used for carrying food and nesting materials. Gophers have small eyes and ears and very sensitive facial whiskers. The large front teeth can be used for digging along with the large clawed front paws. Their cheeks are unique in that they can close behind the teeth to keep dirt out of their mouth when digging.
Gophers live mostly in their burrow. Their burrow system can cover between 200 and 2000 square feet! The feeding burrows are about 12 inches below the ground's surface while the nesting and food storage burrows are as deep as 6 feet, depending on the native soil type. When gophers tunnel, they pulverize the soil and push it out of the opening so it forms a crescent shape and the soil is softer looking than on a molehill. (This is a tempting addition to the garden bed as it is ready to use.). A feeding hole will have no soil around it, although they rarely leave the tunnel to feed. Gophers hide the opening to the tunnel with earthen plugs. Gophers are also active 24/7.
The life span is about 3 years with sexual maturity at about 1 year. They breed in the late winter to early spring and can produce 3 litters/year in well-irrigated areas. A normal litter produces 5-6 young.
GOPHERS ARE PRETTY INDISCRIMINATE HERBIVORES. They eat what they encounter while digging and are known to pull entire plants into their tunnel. They will also gnaw on irrigation lines and utility cables and have been found under houses making a mess of things!
MANAGEMENT of moles and gophers is pretty much the same so I will discuss them together.
Exclusion methods seem to work the best for a home remedy. By exclusion, I mean creating a barrier to the animal getting to the food source. When planting trees, one can make or buy galvanized steel baskets with 1/2 to 3/4 inch square mesh to protect the roots and still allow for normal root growth beyond the basket when planting. (While Steve's dad never did this when planting new walnut trees, he also did not expect all of the new plantings to survive.) The wire eventually rusts and disintegrates and the tree roots are not strangled. One can also create a bed on top of 1/2 inch square wire mesh with barriers at least 6 inches above the ground to keep the SUC's out of the area. (This requires proper prior planning and works quite well.) Another way to create a barrier, especially around a drip or plastic irrigation system is to install it in a trough of gravel.
Repellents - Another remedy is to use plants. Moles do not like plants with strong smells, so any member of the Allium family will deter them. Gophers can be deterred by other strong-smelling plants, such as sage, daffodils, iris, thyme, and geraniums. Gopher purge plants were mentioned in a couple of places. They really didn't work and tried to invade the surrounding orchard! Other deterrents mentioned are fish oil, peppermint oil, coffee grounds, and Tabasco. My grandmother was an avid supporter of coffee grounds and I doubt that she would have ever thrown them in the garbage. (I will be incorporating them into the big area when I replant.). The thing to consider with the coffee grounds is to make sure that what you are throwing them on can tolerate the slightly more acid soil. One method that was mentioned pretty much every place that I looked is to apply Castor oil around the beds and into the tunnels. This causes gastric upset to the animals and they will "move away." However, this must be done regularly. You can buy commercially prepared mixtures or make your own by mixing 3 parts castor oil and 1 part dish soap together and then dilute 4 TBSP mixture into 1 gallon of water. (This is what I will try in my big area and also over at my daughter's.). Other methods that people have told me and that were mentioned include placing broken glass, broken razor blades, fish heads, human hair, bubblegum, pet or human urine into the tunnels. I have done the human hair thing in 1 plot with reasonable success. The urine worked better to keep the turkeys away. The SUC's simply pushed the fish heads back out of the tunnels where I put them. I never did the glass or razor blades just because of safety considerations.
Poison baits were discussed in everything I read. I avoid anything with poison associated because of pets. I have no desire to harm my pets or anyone else's because they caught an animal who ingested poison.
Other methods - Fumigation really doesn't work because of the nature of the tunnels and holes. Flooding also doesn't work and water is a precious commodity not to be wasted. Gas explosive devices had their moment. Remember the "Gophernator"? I do. When the people pulled out the back orchard to put in the olive trees, they used it to clear the field. I wasn't warned and it scared me good. I also wasn't happy when the creatures hit the side of my house! Insecticides came up in most sites. Betsy Buxton just recently did a great blog on why we should not use insecticides in our gardens to discourage visitors to the area who are unwelcome.
Lawn maintenance and keeping garden beds tidy was mentioned but are not completely effective.
I took this picture to show what SUC activity looks like on the lawn. I have no lawn for this reason and also that the dogs would enlarge the hole significantly to find the SUC!
I hope that this information is helpful. Again, I encourage you to look at the IPM site as there are quite a few links to open. I basically chose the most current entries. Going on the regular internet sites offered all kinds of items to purchase.
I don't even want to think about the ground squirrels!