If snails plague your favorite plants, try luring them to a distant corner of the garden by cultivating a decoy patch of stinging nettles. Spanish scientists at the University of Santiago de Compostela found that snails in their experimental plots made tracks straight for the nettles, which—despite the prickles—they seem to find tasty. No snails? Plant nettles for the butterflies, who enjoy the flowers. You'll find prickle-free nettles in your local nursery. They make beautiful groundcovers for shade.