Fireweed or Great Willow Herb [Epilobium angustifolium] found near Cedar Dunes Provincial Park at West Point, Prince Edward Island on 20 August 2015. It’s a member of the Evening Primrose (Onagraceae) family. Newcomb’s Wildflower Guide, pages 130-131, states it blooms in Summer and early Fall on roadsides, in clearings, and burned woodlands. It is quite prevalent along roadsides here in PEI with its distinctive purple shoots. Another shot below was found near Point Prim on 21 August 2015.
USDA Plants Listing: Epilobium angustifolium