Barbara Hainey sent the following email, another testimony to the increasing presence of urban wildlife we have witnessed in recent years.
“My sister and I live in Torrance, a decidedly suburban city. This year, we have both been plagued by a large invasion of raccoons who dig up our lawns on a nightly basis.
Raccoons have long been unwelcome visitors, but this year they seem to be much more numerous, more destructive, and absolutely undeterred. They ignore the chili pepper flakes I saturate the lawn with (heavily, using big-box store containers of chili pepper flakes) and my sister has tried motion-activated sprinklers, all to no avail. Coyote urine and other methods, too, have failed.
This is more of a vent than a plea for help, I suppose, as we know there isn’t any sure-fire way to deter the destructive rascals. We just seem to have SO MANY more raccoons than in past decades. We are far from the burn areas, so I don’t know what the cause might be.”
Raccoons are native to most of North America. Their bones have been found in refuse piles dating to 6,000 BC, an indication that they were part of the diet of Indigenous tribes. “Raccoon” is an Anglicization of “arakun,” the Algonquin name for this animal, whose meaning is “he who scratches with his hands.” Captain John Smith, at the Jamestown colony in 1608, brought this word into the English language unchanged. It was only over the course of time that the “a” in “arakun” was dropped, leaving the rest of the word in its original form.
I have a special fondness for this animal through the coonskin cap, made from raccoon fur with its tail still attached in the back. In the 1960s, I religiously watched the Davy Crockett series on TV; Davy was never without his coonskin cap, and my parents soon had no choice but to get me one too.
Since raccoons are generally looking for grubs, a strategy that targets grubs is advisable. The grubs we see in lawns are usually larvae of scarab or dung beetles. They are the same beetles that were worshipped in ancient Egypt and appear on the tombs of Pharaoh and his family members. The particular type that causes havoc in Southern California lawns is the masked chafer grub, which is most active this time of year. Its depredations may result in dead spots in the lawn, even where irrigation is adequate. Raccoons, coyotes, skunks, and crows are all attracted to lawns that are grub-enriched.
Warm season or tropical grasses such as Bermuda and Kikuyu are more likely to harbor grubs than cool season grasses such as tall fescue (Marathon), ryegrass, and bluegrass. However, cool-season lawns are more likely to show grub damage. Grubs feel at home in the thatch, which builds up in both warm-season and cool-season grasses, although thatch of warm-season grasses is much thicker. To control grubs, apply BioAdvanced 24-hour Grub Killer Plus. According to the label, it “works on contact, delivers overnight results.”
You may be able to eschew chemical control with the help of aeration since just nicking a grub with one of an aerator’s tines is enough to kill it. There is a basic aerator powered by pushing it from behind and a self-propelled, gasoline-fueled aerator, both available from some rental equipment yards. Spike sandals are another aeration option and you can find them via an Internet search. Wear these sandals while traipsing across your lawn. Colorado State University research demonstrated that 3-5 treks across a lawn in spike sandals can reduce grub population by 50%. Prior to aeration, soak your lawn in order to draw grubs to the surface.
One-fourth to ½ inch of water should be applied before aerating your lawn. The soil under lawns is typically compacted and can absorb only 0.2 inches of water per hour. Conventional spray sprinklers apply 0.2 inches of water in approximately 5 minutes, so you will need to water for 5 minutes, wait an hour, water for 5 minutes again, wait another hour, and water for a third 5-minute interval to make sure you have applied the proper amount of water. If you have slow-moving rotary sprinklers, which apply water 3 times slower than conventional sprinklers, you will need to water for 15 minutes, instead of 5 minutes, three times, with an hour between each application.
You may also opt for biological control of lawn grubs. This is achieved through the use of a nematode species (Heterorhabditis bacteriophora), an unsegmented worm that parasitizes and liquefies scarab grubs. An Internet search will reveal vendors who supply beneficial nematodes. Incidentally, the same nematodes that prey on grubs will also parasitize ant, flea, fly, and moth larvae.
Nematodes are easily applied. They arrive in a powdery clay compound that you mix with water. You then water it in with a watering can, hose-end applicator, or pump sprayer. Nematodes are most effective when applied during the cooler times of the day, whether late morning or early afternoon. Grubs are killed within 48 hours of contact with parasitic nematodes, and you can store nematodes in a refrigerator for two weeks.
Control raccoons directly by bringing an owl nesting box into your yard. The nesting box should be large enough to house the California great horned owl, a dominant local species. Although they prefer mice and other small rodents, great horned owls are ferocious birds that will also attack larger critters such as opossums, skunks, and raccoons. I found one on Etsy.com for $159. Install it at a height of 20-40 feet.
Although lawns are often dismissed as too water-needy during recurring droughts, they are actually advantageous when it comes to firescaping – landscaping that reduces the threat of a wildfire engulfing your home. A large swath of lawn surrounding a wilderness home is a good idea. As a wildfire blazes in your property’s vicinity, activation of lawn sprinklers will provide a hydrated buffer to an encroaching inferno. And, in a worst-case scenario, if your house should catch fire, a lawn provides the optimal staging area for fire-fighting trucks and equipment. A fancy landscape with boulders and elaborate fountains or other hardscape features will keep firefighters and their trucks at a distance.
Do you have an urban wildlife tale to tell or a successful pest control strategy to share? If so, send it to joshua@perfectplants.com. Your questions and comments, as well as gardening conundrums and successes, are always welcome.
California native of the week: The vibrant, tubular yellow flowers of rubber rabbitbrush (Ericameria nauseosa) are currently on display, as they have been since the summer. The “rubber” in its common name references the consistency of its sap, and the “nauseosa” in its botanical name acknowledges its scent. Even when not in bloom, this species provides ornamental interest on account of its blue-green foliar needles and whitish green stems. It is vigorous without being invasive and reaches a height and girth of up to seven feet. It is found throughout California, is drought-tolerant, and hardy down to minus 20 degrees.
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