March 28th is National Weed Appreciation Day, but maybe not the kind you're thinking of. Ecologists are reminding Americans that many plants we call weeds are beneficial to us and our ecosystems. Native people have used so-called weeds for food and medicine throughout history. Observers should take the time to identify the many uses of plants that grow in their neighborhoods, but do take caution to avoid herbicides and pesticides if picking weeds for your next garden salad.