Acanthus mollis aka Bear's Breeches

Acanthus mollis is remarkably cold-hardy, rated H6 by the Royal Horticultural Society, meaning it tolerates temperatures down to -15 to -20°C (5 to -4°F) and is hardy throughout the UK and northern Europe. It thrives in USDA zones 7-10, remaining evergreen in warm climates but losing leaves in colder areas. With mulching, it can survive winters in zone 5-6, though young plants benefit from winter protection during their first year.

As a Mediterranean native, Acanthus mollis is not particularly demanding about humidity and adapts well to various moisture levels in the air. It tolerates both humid and dry atmospheric conditions, making it versatile for different climates. The plant's primary moisture concern is soil drainage rather than air humidity—it needs well-drained soil and dislikes waterlogged conditions regardless of air moisture levels.

Acanthus mollis has modest fertilizer needs and performs best in deep, fertile soil enriched with organic matter. While it prefers fertile conditions, it doesn't require heavy feeding and will grow in average soils.

Acanthus mollis produces spectacular architectural flower spikes from June to August, rising 4-6 feet tall above the foliage. The two-lipped tubular flowers are white with striking purple or dusky purple hoods (modified leaves called bracts), creating a snapdragon-like appearance. While the plant can be erratic in blooming and may take 2-3 years to flower from seed, the dramatic floral display—combined with the glossy, deeply lobed foliage—makes it a standout architectural specimen in borders and cottage gardens.

The two most popular cultivars are 'Tasmanian Angel' and 'Hollard's Gold' (also sold as 'Fielding's Gold'). 'Tasmanian Angel' features striking dark green leaves with irregular white margins and mottling, emerging creamy gold then maturing to white—it's the first variegated Acanthus. 'Hollard's Gold' offers broad chartreuse to golden-green leaves that emerge bright gold then fade to acid green, providing the best color in part shade. Both cultivars maintain the species' architectural flower spikes and grow 3-4 feet tall.

Yes, Acanthus mollis is exclusively an outdoor garden plant, thriving in USDA zones 7-10 (hardy to -15°C with proper care). Native to the Mediterranean, it excels as an architectural perennial in borders, cottage gardens, and Mediterranean-style landscapes. Plant in full sun to partial shade—preferring afternoon shade in hot climates—with well-drained soil. It's ideal for creating bold focal points but requires careful siting as it spreads aggressively via rhizomes and can become invasive in some regions.

Prune Acanthus mollis by cutting down old flower stems after blooming finishes in late summer. In cold climate zones, leave the foliage intact through winter for protection, then remove any dead or damaged leaves in early spring before new growth emerges. In warm climates where the plant remains evergreen, you can tidy the foliage as needed throughout the year. The RHS advises against relocating established plants, as new shoots will emerge from deep roots left behind.

Acanthus mollis propagates easily through three methods: division in spring or autumn, root cuttings taken in early spring or winter in a coldframe, and seed sown in spring at 10°C (germinating in 3-4 weeks). Division and root cuttings are preferred for faster establishment, while seed-grown plants may take 2-3 years to reach flowering maturity. The plant's aggressive spreading via rhizomes means propagation is rarely needed—controlling spread is often more challenging than creating new plants.

Acanthus mollis is generally pest-free but faces occasional issues with slugs and snails that damage the large leaves, particularly on young growth. Powdery mildew can appear on foliage in humid conditions or areas with poor air circulation. Control slugs with barriers, traps, or organic pellets; manage powdery mildew by ensuring good spacing, air circulation, and removing affected leaves. The plant is notably resistant to deer browsing, making it valuable in areas with deer pressure.

Acanthus mollis is hermaphroditic (having both male and female organs) and pollinated primarily by bees. The tubular white flowers with purple hoods are specifically adapted to attract bee pollinators, with the purple bracts serving as visual attractants. The flowers bloom from June to August, providing a valuable nectar source for bees during the summer months.

No, Acanthus mollis is not edible. Plants for a Future (PFAF), a comprehensive database of useful plants, rates it 0 out of 5 for edibility with no known edible uses. While the plant is non-toxic and won't cause serious harm if accidentally ingested, no parts are cultivated or recommended for consumption. It is grown purely as an ornamental plant for its architectural foliage and flowers.

Acanthus mollis has traditional medicinal uses, with the leaves and roots containing appreciable quantities of mucilage and tannin. These compounds provide astringent, detergent, emollient, and vulnerary (wound-healing) properties. Historically, the plant was used externally as poultices and pastes to treat dislocated joints and burns. Internally, the emollient properties help soothe irritated mucous membranes in the digestive and urinary tracts. However, these are traditional uses, and the plant rates only 2 out of 5 for medicinal value.

Beyond ornamental use, Acanthus mollis serves as an effective ground cover plant, particularly the subspecies A. Most famously, the plant's distinctive leaves were used as the model for the Corinthian leaf motif in ancient Greek and Roman architecture—you'll find acanthus leaf designs carved into column capitals, friezes, and decorative moldings throughout classical and neoclassical buildings. This architectural legacy represents one of the most enduring cultural uses of any plant species.