Dandelions
Yarrow
Wild mushrooms
Elderberries
Lamb's-quarters
Plantain
Burdock
Wild grapes
Nettles
Catnip
Black walnuts
Wild rice (permit required from Minnesota DNR)
Picking tips: "Pick plants as if you're in the produce section. Look for fresh, healthy and happy specimens," said Minneapolis herbalist Lise Wolff. Harvest conservatively, leaving plenty of leftovers for wildlife and other foragers (and for yourself, perhaps in future seasons).