MAY / JUNE 2005

We lurch from crisis to crisis

In the early 20th century, a blight rendered the grand American chestnut tree virtually extinct. Mid-century, Dutch elm disease barreled in. More recently came the Asian long-horned beetle that denuded several city blocks in Chicago. Now the emerald ash borer, which has killed at least 6 million trees in southeastern Michigan during the past five years, is following Horace Greeley’s famous dictum and going west. At last report, it had set foot in Indiana.

The question is not only how to stop it, but what to do after we suffer major losses from tree infestations. The typical response has been to replant with some new monoculture, something relatively cheap and easy—like the ash trees that succeeded American elms. But what to plant now? Maples are a favorite food of the Asian long-horned beetle. Oaks are susceptible to oak wilt, sudden oak death and gypsy moth. Lindens are vulnerable to certain borers. And while chanting the native plant mantra may help, not all native trees are suitable for sidewalk parkways or small residential yards.

One key is to rethink that word “monoculture.” Because it makes any disease or pest attack more devastating, it has led American agriculture down the slippery slope towards increasing dependence on pesticides and herbicides, and it is doing the same for our municipalities and park departments. Home gardeners also need to reject monoculture and embrace biodiversity. Reduce the size of those massive sterile lawns and turn them into vegetable patches or perennial borders or herb gardens. “The more the merrier” should be our slogan.

In my early gardening years, I had aphids. Always, by mid-summer, the tips of roses and tomatoes were encrusted with them. Then a few years ago, I suddenly realized that I no longer had a problem. Why? Although I can’t prove it, I think the fact that I had been cramming my garden with every new plant I could find room for—especially native prairie plants—had a lot to do with it. As the multitude and variety of plants increased, the garden started attracting insects I had never seen before, and since most insects are beneficial, I figure the good guys ate up the bad guys.

Writer Michael Pollan articulates a more comprehensive version of this argument in his book Second Nature. Rather than spewing gloom and doom, he points out that while human beings do destroy nature, they can also improve it, and this is particularly the job of the gardener. A garden is not nature. It is not even natural. It’s man-made and therefore artificial. But it can be something good. It can be a second nature.

Keep that in mind as you go shopping this merry month of May. Scout out those tall blue salvias you’ve never grown before. Inundate your space with the heavy, luxuriant fragrance of Orienpet lilies, try some heirloom tomatoes, and rejoice as you decorate your shady garden with all those gorgeous plants that are really happiest when they can just sit quietly under a tree. So get out there. It’s time to do our bit for biodiversity.