HARDINESS: Zones 3 to 8
PREFERRED SOIL pH: Near neutral
PREFERRED SOIL TYPE: Average
PREFERRED LIGHT: Sun to shade
ATTRIBUTES: White plumes of flowers, graceful foliage; for back of border, as specimen
SEASON OF INTEREST: Spring through fall
FAVORITES: Giant A. dioicus; cut-leaf A. dioicus 'Kneiffii; dwarf A. aesthusifolius
QUIRKS Male plants have showier flowers than female plants
GOOD NEIGHBORS: Astilbe, cohosh, hellebore, hydrangea, ferns, Japanese anemone
WHERE IT GROWS BEST: Shade, moist soil, cool-summer climates
POTENTIAL PROBLEMS: A. dioicus is difficult to move once established
RENEWING Lives many years; divide crowded clumps only when necessary
CRITTER RESISTANCE: Excellent
SOURCE: Bedding plants, division
DIMENSIONS: 3-5 ft (1-1.5 m) tall and wide; dwarf, 12 in (30.5 cm) tall and wide
Goatsbeard in the Landscape
Goats beard is great for growing in masses as a backdrop for smaller plants. A care-free shade lover where summers are hot, goatsbeard accepts more sun in cool climates. Although the giant goatsbeard grows more than 5 ft (1.5 m) tall, compact varieties are available for smaller gardens. Male and female flowers are on separate plants. The males have fuller sprays of feathery flowers, making them better subjects for gardens.
Goatsbeard flowers resemble those of astilbes. They start off a greenish white and then turn to creamy white, sending forth a faint scent as they mature in summer. The restful flower color and grass green oval leaves blend well with virtually all other plants, easing the transition nicely from one color scheme to another.
From Prodigious to Petite
The king of goatsbeards, Aruncus dioicus, is perhaps the most statuesque of all shade-loving hardy perennials. It can be gangly when young, but give it a few years to put on girth and it becomes a truly magnificent plant, resembling a huge astilbe. It forms a dense, well-shaped mound of foliage, eventually attaining a height of 6 ft (1.8 m) when in flower, with an ample 5 ft (1.5 m) width. Use it at the rear of a border, mass it in naturalized areas, or display it as a specimen.
A. dioicus 'Kneiffii' is a smaller cultivar sized for any garden at 3 ft (1 m). While the flowers are like those of the species, the green leaves are deeply divided into threads, much like cuteaf Japanese maple foliage.
At the other end of the size scale is a truly dwarf plant called Korean goatsbeard, or A. aesthusifolius.This beautiful little goatsbeard grows only 12 in (30.5 cm) tall, with a lush show of deeply divided, ferny leaves that become brushed with bronze in the fall. Studded with open bottle-brush-shaped sprays of creamy flowers in summer, dwarf goatsbeard is excellent for small gardens, the top of a retaining wall, or containers.
In regions with cool summers, goatsbeard can adapt to either sun or shade, but in Zone 7 and warmer climates it needs a shady shelter from the afternoon summer sun. Goatsbeard likes moist soil, but established plants grown in the shade can tolerate dry conditions and root competition from trees. For best results, amend garden soil with generous quantities of aged manure, compost, or leaf mold before planting, and mulch annually with the same materials to help retain soil moisture.
When finding a home for giant goatsbeard, select a spot with care, because after a few years it develops a massive root system that requires a monumental effort to dig up. Its wandering roots are undoubtedly the reason it is quite drought tolerant once established. To divide goatsbeard, dig the plants in early spring or fall and divide them by sawing the rhizomes apart, making sure each piece has at least one prominent, fleshy, up-facing growing tip. Goatsbeard can withstand a lot of rough handling, but take care not to snap off too many of the growing tips when replanting. Set the divisions at the same depth the parent plant grew and water them thoroughly after replanting. Aruncus are hardy and blessedly free of problems from pests and diseases.