A classical Plant from Ancient Greece
Common Name: bear’s breeches
Botanical Name: Acanthus mollis
Form: clump-forming rosette
Plant Type: herbaceous perennial with tuberous roots
Mature Size: 3 to 5 feet x 2 to 3 feet
Hardiness Zone: 7 to 10
Foliage: emerge from a rosette, dark green, glossy, deeply lobed, up to 36” long and 12” wide
Flowers: maroon-purplish and white 2-lipped, hooded flowers up to 2” long are surrounded by spiny bracts, borne in vertical rows on erect leafless stems up to 5ft tall in summer
Fruit: one or two brown seeds in a pointed capsule
Exposure: sun to partial shade, avoid hot summer afternoon sun
Soil: soil tolerant, dislikes wet soil
Uses: accent, foundation plant, specimen, formal gardens, woodland edges
Propagation: root division, seeds
Pruning: remove flower stalks after flowering
Problems: invasive where conditions are favorable
Carl Linneus, the noted botanist and ‘Father of Taxonomy’, first described this historical plant in his book Species Plantarum in 1753. The large, deep green, attractively ornate foliage were the inspiration for Greco-Roman and Classical architecture. This ‘Corinthian’ design was carved into columns, and has been used throughout the ages denoting a classical elegance that is still revered today.
Bear’s breeches, Acanthus mollis, makes a bold but elegant and classical statement that never goes unnoticed. Even without its towering snapdragon-like flower spikes, their large 3 foot leaves are very attractive and stand out even when mixed with other greenery. In warm climates, the foliage will stay evergreen, but will go dormant when temperatures dip to below freezing.
Although they are soil tolerant, soggy soils promote rot. Lack of flowers are caused by too much shade or from late spring frosts. To protect the crowns and potential blooms, don’t remove their foliage in fall, instead cut them off in spring as new growth emerges.
Keep plants away from hot afternoon sun as this may cause wilting. They will also go dormant in summer if they are not watered.
Bear’s breeches spread via underground tubers and seeds. This is why it is important to remove the spent flower spikes before they go to seed. Tubers will spread in warm climates and when grown in loose soils. In areas where they are too aggressive, install an 8 inch barrier to confine their roots. This plant is invasive in parts of California, Australia and New Zealand.
Other Cultivars and Species:
Acanthus mollis ‘Latifolius’ are hardier, but doesn’t flower as freely as the species and have larger foliage. Zones 7 to 10, 2-2.5′ x 2-3′.
Acanthus spinosus is an alternate species know for leaves with spines along the edges (margins). Zones 5 to 9, 3’ - 4’ x 2’ - 3’.
Acanthus balacanicus, Balcanicus Bear's Breeches, flowers profusely, with white or pale pink flowers, with deep lobes spaced far apart. Zones 7 to 10, 2’ - 4’ x 2’-4’.