Common Pokeweed (Phytolacca americana)
Comments: "Flowering: July - September... Habitat: Open woods, damp thickets, clearings, and roadsides... This frequently troublesome weed has poisonous berries and roots; however, emerging young shoots can be gathered before the pink color appears, boiled in at least two changes of water, and eaten as greens. The berry sap was used as a dye by the early colonists and has also been used to color cheap wine." - NAS Field Guide to Wildflowers
An important, fast-growing food source for many birds. I once had a five-foot tall plant emerge in my garden over a long weekend.