Cats and bugs are a constant nuisance to gardeners, but lemon grass repels them both –– and also serves as mulch.
The lemon grass was a guess, but it was a good guess.
The problem we were addressing was cats. I am not one who rejects cats out-of-hand. Their grace and stealthy affection intrigue me. In our yard are headstones memorializing two beloved cats killed post-Katrina (don’t ask). But these cats –– ferals fed by a neighbor –– were using my raised vegetable beds as a bathroom, and this had to stop. After excavating and replacing the soiled dirt, seedlings and all, I turned to the Internet and the gardening books for solutions.
It is not news that common American shorthair cats are sensitive to smells. Smells that repel them include peppermint, citrus, lavender, coffee, mothballs (camphor) and eucalyptus. Vinegar is also unpleasant enough to deter them. Other helpful hints included scattering red pepper flakes across the garden to burn their noses and setting up an outdoor kitty box so they’d have an alternative place to mess.
Then there was the final solution proposed by my gardening partner, which consisted of an oversize Havahart trap and a trip to the LA/SPCA.
It was somewhere between the discussion of where to buy an industrial tub of red pepper flakes and an attempt to get the trap back into storage that my eyes lit on the lemon grass growing by the fence. Started from a purchased 6-inch pot three years ago, our lemon grass (Cymbopogon citrates) has morphed into four sumptuous 5-foot-tall clumps, each about 2 feet in diameter. These require no care apart from an occasional shot from the hose. The grass grows back readily when you cut it to a height of 6 inches. And it smells powerfully of the very citrus that cats abhor.
Armed with a small pair of garden clippers, I gathered an armload of lemon grass shoots, barbering a plant-and-a-half in the process of trying to protect two 3-foot-by-12-foot raised beds. Not sure how to proceed, I chopped my harvest into tiny bits to release as much scent as possible. These chips were arranged between the rows of beets, lettuce and peas that the cats hadn’t soiled. In areas where I already had excavated and replaced the soil, I laid the lemon grass pieces down in a thick blanket. Cats have good memories, and I wanted to be sure they got the point.
Three months later, I can say confidently that the cats have not returned to my garden, nor have new cats ventured in. They’re still around — I catch one big tom slipping through the back fence on a regular basis –– but they leave my vegetable gardens in peace. To replenish the scent, I cut new shoots to replace the old ones every six weeks. That allows the lemon grass time to recover, which it does amazingly well. I have yet to encounter a shortage of shoots when it’s time to cut more. In my alkaline, unimproved soil and not-too-wet yard, the stuff grows back like grass.
An unexpected advantage of this homegrown solution was mulch. Laid between rows, the lemon grass provided an excellent mulch that did not seem to adversely affect the pH of the plants. As an added benefit, I quickly observed a diminishment of other pests in the garden. Gone were the little flea-like things that feasted on the beet shoots; gone were the trapezoidal beetles. I don’t think the lemon grass is caustic enough to banish all of the organisms in the soil, many of which are beneficial and help nourish plants. But I quickly found that I had fewer bugs to pick off and squish between my fingers when I went out to the vegetable garden in the mornings. This was the case only in the beds where I had placed lemon grass. The flower beds, which never received this treatment, remained lively with pests.
My most trusted source on pest control, The Organic Gardener’s Handbook of Natural Insect and Disease Control, edited by Barbara W. Ellis and Fern Marshall Bradley, makes no mention of lemon grass used in this way. Like many gardening books, however, this one is written for audiences in temperate climates where lemon grass (a zone 10-11 plant) won’t survive. On the Web, I did find numerous references to lemon grass as an effective mosquito repellent, recommending it for its high citronella content. According to several writers, you simply mush the pulpy, scallion-like lower stems of the lemon grass shoots with your hands; mix the result into alcohol or water; and use it as a spray.
It’s a constant challenge, I find, to discover gardening solutions that are actually tailored to our climate rather than roughly adapted from temperate-zone approaches. But I was thrilled with this one, which involves a tropical plant that fights tropical bugs. Best of all, of course, is the fact that it doesn’t hurt the cats.