I bought some Aruncus Diocius plants through the mail. I wasn't sure how to plant them. Are they roots?

The long feathery parts are the roots. So you did plant them correctly.

This perennial grows up to 7 feet tall. Sprays of tiny white flowers bloom briefly but spectacularly for two weeks in early summer. Its native environment is the semi-shade of woodland clearings and it is most attractive in this setting. In the wildflower garden it makes an imposing background plant, especially when displayed in an isolated grouping. Each flower spray contains thousands of tiny blossoms, which rise in loose blooms 6 to 10 inches above the foliage.

In a mixed border, place Goat's beard in the back both because of its height and because its bloom season is short and the attractive foliage will make a nice backdrop for shorter, longer blooming plants.

The plants are either male or female; one plant does not contain both sexes.

Aruncus will grow in almost any soil, and in sun or partial shade. The soil should be moist. Buy quality nursery stock or start plants can be grown from seeds, which germinate readily.

Dividing established root clumps in the spring or fall can also propagate. These plants need little care as long as the soil remains moist; they will survive indefinitely if left undisturbed.

Type: perennial
Propagation: division, seeds
Light: sun or partial shade
Flower Color: white
Height: up to 7 feet
Width: 2-3 feet
Soil Requirements: almost any soil, moist
Zones: any
Uses: Back of the border or in groups, woodland settings