How to Plant, Grow, and Care For Acanthus
Acanthus brings bold, structural foliage and form to the shady border. Join gardening expert Katherine Rowe in exploring the handsome architectural perennial that thrives in partial sun and shady garden sites.
Acanthus is an architectural perennial with bold vertical interest and....
handsome, lush leaves. The scrolling foliage unfurls to form broad, frond-like leaves with a tropical look.
Distinctive bloom spikes emerge in early summer on tall stalks, densely lined with creamy white and purple flowers to steal the show. The lush, glossy specimens grow primarily for their ornamental leafy structure with the added benefit of the towering bloom spikes.
In the right situation, Acanthus grows easily with little maintenance and long-lasting display qualities.
Acanthus Overview
What is Acanthus?
Acanthus, or bear’s breeches, comprises about 22 species from Europe, Asia, and Africa, with a long garden history. The architectural specimen has dark, glossy, deeply lobed leaves. The name is from the Greek “akantha,” meaning spines, in reference to the spiny leaf margins on some species.
The specimens appear as early as the fifth century in architecture and art. As a leaf motif in ancient Greek and Roman architecture, they adorn Corinthian column capitals. In Greek mythology, Akantha was a nymph who rebuffed the god Apollo’s romantic advances, for which he turned her into a thorny plant.
Acanthus is stately in formal and informal settings as specimens or small groups. Pair them with hosta, heuchera, ferns, iris, astilbe, epimedium, and Solomon’s seal for gorgeous layered combinations. Annuals like begonia and caladiums share the same growing conditions. Their blooms also make striking cut flowers.
The vigorous growers spread through rhizomes to form clumps. In optimal conditions that mirror their Mediterranean climate, they spread aggressively. Some are invasive in Oregon and California. They root easily and can be difficult to remove once established. Most varieties benefit from being kept in bounds by walkways or edging. In areas with winter climates or hot summers, plants are more well-behaved with less spread. Hybrids are more compact and better behaved, suited to various garden situations.
Characteristics
Bear’s breeches’ long, basal leaves have sturdy central spines and form a rosette. In spring and summer, tall bloom spikes appear with vertical rows of creamy white flowers and purple-rose bracts. The hooded, two-lipped blooms line the spikes and resemble a large foxglove or oversized snapdragon.
The perennials are drought-tolerant, deer and rabbit-resistant, with few pest and disease issues. They may be slow to establish but settle in by the second growing season.
Several of the species are in cultivation. A. mollis and A. spinosus and their cultivars are the most widely grown for ornamental landscapes.
A. mollis is a popular, historic European species that grows four feet tall and two to three feet wide. The bloom spikes top five feet in late spring and early summer. Individual flowers measure one inch.
A. spinosus grows three to four feet with summertime blooms in June through August. The flower stalks rise three to four feet tall above the foliage. Leaves are deeply cut with spiny margins.
A. hungaricus resembles A. spinosus but with slightly less divided, spiny foliage in dense clumps. It has pale pink to white flowers with attractive, ornamental leaves. This species is synonymous with A. balcanicus.
A. montanus, or mountain thistle, is indigenous to tropical climes of West Africa. Hardy in zones 7 to 10, plants reach four to six feet tall. The shrubby perennial has deeply lobed, symmetrical leaves up to one foot long in silver and dark green. Mountain thistle is most susceptible to winter damage in lower zones.
A. dioscoridis is native to Turkey, Syria, Armenia, and Iran. It has pink petals in early summer and divided leaves on one to two-foot plants.
Acanthus sennii, or Ethiopian bear’s breech, grows at high elevations. Dark, glossy leaves have black stems. Late summer and fall flowers are bright red-orange.
Native Area
The ornamentals are native to Mediterranean climate zones with loose, well-draining soils and moderate temperatures. They grow in woodlands and slopes as understory spreaders.
Occurring naturally in arid, mild climates, they may fade in heat and humidity or extreme winter conditions. Some hybrids perform well across zones without aggressive spreading.
Planting
As a rhizomatous spreader, Acanthus gradually forms a clump and continues to sprawl in optimal conditions. Planting it near a walkway or bounded bed helps keep it in check. Root barriers or areas where it has room to run work, too. When planting, space plants three feet apart to allow for air circulation.

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