Just in time for gardening season comes Janet Raloff's readable and insightful piece on exotic garden plants that escape to become invasive weeds. She makes interesting and relevant to the nation's millions of gardeners some important and overlooked truths and without the killer-bees-are-coming hysteria that mainstream media often lapse into. The best of the piece is in anecdotal specifics -- the liriope in her own backyard lulling her into complacency just before the invasion. Still, she also informs us that while "only about 10 species out of 1,000 new introductions will prove weedy," nonetheless, "more than a quarter of all plant species now growing in the United States evolved elsewhere." She describes the tree ailanthus (euphemized as the Chinese Tree of Heaven) that actually sends out toxins from its roots to poison the competition, a fact that biological weed control researchers hope to capitalize on. This article is good enough to make an environmental reporter want to cover the next meeting of the Federal Interagency Committee for the Management of Noxious and Exotic Weeds. But it also leads to a local story in just about every city, state, and ecoregion. (See: http://www.sciencenews.org/20030412/bob9.asp)