How do I get it to bloom? It is about 10 years old and only bloomed the first year after planting. It has always gotten lots of seedy "plumes" but none have blossomed into any beard resembling anything close to the white feathery plumes of that first year.
They can be picky and definitely prefer to stay moist. Aruncus dioicus ( Goats Beard) is dioecious so it has separate male and female plants. Yours may be the female variety where it has tons of seed plums and is less likely to flower.