There is drama and there is high drama. Aruncus diocus or giant goat’s beard is high drama, looming up to 180 cm, bearing creamy-white plumes that rise above the dark foliage and brightening up the shady garden. Susan Lipchak, one of the master gardeners featured in Gardening from a Hammock, suggested both the giant Aruncus diocus and the smaller Aruncus dioicus ‘Kneiffi’, cutleaf goat’s beard, for the shade. “The Aruncus diocus is a dramatically bold plant because of its size – it looks like a giant astilbe,” says Susan. It holds its own beside a giant clump of tall grasses in her garden. This perennial stands between 120 to 180 cm and is spectacular in flower with its creamy white plumes and lacy leaves. It eventually forms a dense clump. The ‘Kneiffii’ variety is smaller, but still stands 90 cm and has finely cut leaves, which would suit a smaller garden.
The giant goat’s beard is ideal for the back of a shady border or beside a pond. It needs room, as it will spread between 90 and 150 cm. Expect a strong statement from the creamy-white flowers June through July. Where the giant goat’s beard would be too large, the more compact cutleaf goat’s beard (Aruncus dioicus ‘Kneiffii’) would provide the impact without the height. It is smaller at 75 to 90 cm high, but with the same spread. It has finely cut leaves similar to a Japanese maple with creamy-white flowers June through July.
As an interesting aside, the male flowers produce showier and more erect plumes (I am not making this up) than do the plants with female flowers.
To get new plants, divide clumps in spring or fall, but be aware they do not like being moved.
Giant goat’s beard is one of the star plants selected by 17 expert gardeners in Gardening from a Hammock by Ellen Novack and Dan Cooper. Gardening from a Hammock is an easy-to-use book describing how to create a fabulous, four-season garden using low-maintenance plants. It’s loaded with tips and has a botanical reference guide.