Hemp Dogbane (Apocynum cannabinum). Brooklyn, NY. By chain link fence on east side of Flatbush Ave between Kings Plaza Marina & Nick's Lobster House. This is the same population previously identified as Apocynum androsaemifolium. However, the consistently white (not pink) flowers with the corolla lobes erect (not reflexed) indicate these plants are Apocynum cannabinum and not Apocynum androsaemifolium.