The Land Planarian

Encountering this 10-inch-long flatworm in the garden or on the sidewalk after a rain can be a little unnerving to the gardener. True, for most of its extra-long body, it looks and feels like a worm, but, oh, that head!

The land planarian is an import that's slowly and successfully spreading around the world. Originally from southeast Asia, it usually arrives in the landscape via potted foliage plants. It's not harmful to the gardener — except for the shock of finding one — and it comes with a bag of tricks. It can hang from branches via a line of mucus, it can reproduce by dividing (in addition to laying egg capsules), and with a finely honed sense of chemical smell, it can find its prey. And therein lies the problem. Among its favorite prey are earthworms, and it's been known to decimate earthworm populations. Some land planarians are relatively small — only about 2-1/2 inches long — but they nevertheless can take on and kill an earthworm much larger than themselves. Worm growers have reported losing significant numbers of their populations to these predators.

What's a gardener to do? If you find one in the garden, remove it. You might also consider calling your local extension agent to report that you've spotted one.

The land planarian needs a humid environment — or microclimate — in order to live. So far it's been spotted in various states throughout the East, Southeast, South, Pacific Northwest and California.