|I inherited a plant from my mother many years ago. She and my grandmother called it "Washington's Plume". I have looked in every book available to me in vain. It has a tall flowerstalk with feathery flowers, not unlike heliotrope.
|If it's a perennial, could it be Gay Feather (Liatris)? These plants have narrow stems with narrow leaves topped by a plume of small, fluffy rose-purple (or white) flower heads. Or, perhaps it's Astilbe, which produces stiff stems with feathery-looking blooms.
Hope one of the above is an exact match!