Perennial Plant Feature--Goat's Beard
By Dr. Leonard Perry, Extension Professor
University of Vermont
If you are interested in naturalistic gardening and using native plants, the Goat's Beard (Aruncus) is an excellent candidate for your garden. Native to North America, the Goat's Beard is hardy in zones 3 through 7. The main species (dioicus) is native throughout northern regions of the world.
It was known even in Roman times, being given the name Aruncus by Pliny. This genus of perennials is in the rose family, being closely related to the Spirea shrub and the Meadowsweet perennial. It resembles most closely, however, an Astilbe.
It is happiest in part shade in the South and full sun in the North. This is one of the many perennials happier in cooler climates. It does need adequate soil moisture. Too little, and the leaf edges will turn brown, especially if in the sun. Leaves are pinnately compounded--divided into separate leaflets--and not particularly showy.
Blooming in late spring in the South, early summer in the North, it has dense spikes of creamy white flowers. Rising above the leaves, the flowers reach four to six feet tall. The flower spikes grow up to 12 inches long and are unusual in that they are composed of unisexual flowers.
Some plants have male flowers, others female flowers that form fruit. This is known as "dioecious" in plants. Although some say the male flowers are showier, most feel the two types are hard to tell apart, especially at a distance.
Since Goat's Beard may spread from two to six feet across, it should be given plenty of room when planted. It is difficult to transplant or divide later on, and with adequate space, this should not be needed. It spreads by means of creeping rhizomes (ground stems).
To propagate plants, seed is the preferred method. Harvest fresh seed and sow immediately. If this is not possible, store seed at 40 degrees F (in the refrigerator), moist, for at least four weeks before sowing.
Of the main species of Goat's Beard (dioicus), there are a couple cultivars (cultivated varieties) you might see. 'Glasnevin' is an introduction from the Irish Botanical Gardens and has deeper green leaves and shorter height than the species. 'Kneiffii' has deeply cut foliage, which appears threadlike, and is only three feet tall. Its flowers are less showy than the species.
The only other important species of Goat's Beard is the Korean Goat's Beard (aethusifolius). This is very different, being only six to eight inches high, and 12 inches across. It has deeply cut, dark green leaves, and creamy white flower spikes above the foliage. As its name indicates, it is native to Korea. Use this species in the front of shade borders, massed in woodlands, or partly shaded rock gardens.
For more details on Goat's Beard, as well as on many other choice perennials, check out Perry's Perennial Pages (http://www.uvm.edu/~pass/perry/) on the Internet.
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