If you hike a lot, or go for walks in parks, you’ve probably memorized what poison ivy looks like—and if you haven’t, you should. Leaflets clustered in threes, let it be, and all that. But as summer ...

If you are homesick for the East Coast’s or Midwest’s fall colors in the woods, enjoy the autumnal red of poison oak — from a distance! Poison oak is incredibly varied. It can be a vine festooning ...