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Family: Viburnaceae (Moschatel family)
Mid-Atlantic bloom time:
late April - July
Mid-Atlantic fruit ripe:
July - August
While the ripe fruits (known as elderberries) of Common Elderberry are considered edible, all other parts fo the plant (including unripe elderberries) contain potentially toxic chemicals. It is closely related to the European Elderberry (Sambucus nigra), and it is sometimes treated as a subspecies of that as Sambucus nigra ssp. canadensis.
References
1: U.S. Forest Service, Plant of the Week: American Black Elderberry