Aruncus dioicus is a wide-ranging species occurring from Canada south to Alabama, and from western Europe into southern Russia...as you can see, it has boundary issues. Some taxonomists are trying to split the two species, so stay tuned. Imagine an astilbe on steroids and you can visualize Aruncus dioicus. The elegant 5' tall clumps are topped with astilbe-like plumes of white in April/May (NC). Moist, organically rich soils are preferred. Aruncus dioicus was named as one of the top 200 plants of the last 200 years by the Royal Horticultural Society...quite an honor.