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Q. Dear Umbra,

So cacti can remove selenium from soil. I’ve read in the past about different plants being able to “sop up” various nasty chemicals. My question is this: Then what? Are they to be harvested and dumped somewhere, so contaminating another piece of land, or are they allowed to live out their lives, die, keel over, and re-contaminate the same piece of land?

David B.
Greenfield, N.H.

Photo by Tommy Wong.

A. Dearest David,

Is there anything our plant friends can’t do? They look nice, they often smell nice, and they agreeably exchange their oxygen for our carbon dioxide. They sequester carbon, they feed us, they shade our homes, they shelter critters, they make indoor air cleaner, they improve worker productivity, they can be ground up to make medicines and teas. I could go on and on. Or maybe I couldn’t, because I’m getting all choked up just thinking about the sacrifices plants make for us, the dunderheaded humans who lurch among them.