Acanthus: Planting, Growing and Care

Botany

Bear’s Breech or Acanthus is a perennial plant from the Acanthaceae family, primarily native to the Mediterranean basin where it grows in dry, rocky areas. The genus includes around thirty species of varying heights, with six species endemic to Europe. The most common in our gardens are Acanthus mollis or soft-leaved bear’s breech, with white flowers tinged with purple on spikes reaching up to 1.50 m, and Acanthus spinosus or spiny bear’s breech, with spiny foliage and white flowers featuring pink, also spiny bracts.

You can also find Acanthus hungaricus, smaller (80 cm), with spineless leaves, the hardiest and most floriferous species in the genus. Acanthus hirsutus, with its semi-erect leaves, doesn’t exceed 40 cm in height. Some hybrids, like Acanthus ‘Whitewater’, are highly sought after for their variegated foliage.

Fast-growing, this spreading perennial expands from a fleshy rootstock, quickly forming large clumps over the years, which can sometimes become invasive. It can naturalise in gardens and will self-seed readily if conditions are favourable. Its roots can draw and store water deep underground during dry periods.

This is a plant with a majestic habit, bushy, dense, upright or semi-erect (A. hirsutus), more or less spreading, reaching up to 1.80 m in height when flowering for Acanthus mollis, with a spread of 1.20 m. Bear’s breech varies in size and shape from one species to another.

Acanthus mollis – Botanical illustration

Bear’s breech is a large perennial grown for its deciduous or semi-evergreen, highly ornamental foliage, whose sculpted motif has adorned Corinthian capitals since ancient Greek times.

In spring, the fleshy rootstock produces rosettes of leaves that form a lush clump emerging from the ground. They vary in size, shape, and number of lobes.

Spectacularly large leaves, with long petioles, ranging from 8 cm to 1 m in A. mollis and A. spinosus, glossy or hairy, dark green sometimes marked with silver or variegated with creamy white or golden yellow turning green with age (Acanthus mollis ‘Hollards Gold’), appear. Oval and toothed, opposite and elongated, they are more or less deeply lobed with spiny or spineless edges depending on the species, down to the prominent midrib. The leaves of A. mollis are deeply cut without true spines. The leaves of A. spinosus have paler veins and almost white spines. In A. hungaricus, each lobe is narrowed at the base.

Some resemble dandelion leaves, others artichoke leaves. This foliage disappears completely after flowering but may reappear in autumn in mild climates. It provides a perfect backdrop for its spectacular summer-long flowering spikes.

From June to September, as the foliage tends to wither, impressive tall flower spikes emerge, rising 20 cm to 1.50 m above the foliage depending on the species. In some cultivars, the flower stems take on a purplish-pink hue.

Regal, these upright spikes bear clusters of tubular, two-lipped flowers 3 to 6 cm long, well separated from the foliage, grouped in fours and arranged along sturdy stems. Watch your fingers—these flowers prick! Each flower is topped by hairy, often spiny bracts. Shaded with purple, violet, pink, or more rarely greenish-yellow, these hoods give a bicoloured effect to this white, cream with pink reflections, green, yellow, pink, or purple flowering.

Hungarian bear’s breech, Acanthus hungaricus

Though not fragrant, they are nectar-rich, attracting pollinating insects. This flowering lasts for weeks.

Bear’s breech flowers make lovely fresh summer bouquets. The dried inflorescences are highly decorative in vases.

After flowering, the corollas give way to small shiny capsules, the fruits, containing four large seeds. The hood remains during fruit formation, turning dark brown.

Hardy, bear’s breech is a vigorous plant that can withstand temperatures down to -15°C. Some, like Acanthus spinosus, are less cold-tolerant. But all are easy to grow in dry soils and full sun.

Bear’s breech grows quickly in any reasonably rich, deep, well-drained soil that stays moist in autumn and spring. It only fears winter wetness. It will adapt even to chalky, stony, and dry summer soils. Some even grow in scree.

From its Mediterranean origins, it retains good drought resistance. It thrives in full sun, where it flowers profusely, but prefers partial or full shade in very hot climates. It dislikes being moved, as once established, it develops an extremely long, spreading root.

Bear’s breech is a striking architectural perennial with ancient charm, always making a statement in the garden. It is highly valued for structuring prairie-style gardens, adding height and volume to perennial or colourful annual beds. It also works well as a standalone plant, introducing vertical accents and focal points at the back of borders, in edgings, or even in pots near the house.

Species and main varieties

There are around thirty species of Acanthus, but only a few are cultivated, still offering a lovely choice of flower colours and foliage. All are hardy and form sturdy, dense clumps that are highly ornamental.

The most well-known and widespread in our gardens is the imposing Bear’s Breech (Acanthus mollis), with its white and purple-tinged flowers and large, deeply lobed, non-spiny leaves that can grow up to 1 metre long; it is also the tallest, with flower spikes reaching up to 2 metres in height.

Foliage and flowering of Acanthus mollis

It has given rise to Acanthus mollis ‘Rue Ledan’ (Jeff Albus), a variety distinguished mainly by its white flowers topped with a greenish hood. The cultivar ‘Hollards Gold’ develops golden-yellow leaves that turn green in summer, while the Acanthus ‘Whitewater’ boasts striking white-variegated foliage.

Another commonly found species is Acanthus spinosus, which forms a beautiful clump with spiny, deeply lobed foliage. It is more invasive than A. mollis and is often used as ground cover for difficult slopes. Acanthus hirsutus is the smallest, reaching no more than 40 cm in height at maturity.

Acanthus spinosus – flowering and foliage

Acanthus hungaricus, also known as Hungarian Bear’s Breech or Balkan Bear’s Breech, is smaller but the most floriferous and vigorous of all Acanthus species. Its leaves are non-spiny and narrower than those of Acanthus mollis.

Most Popular

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Acanthus mollis - Bear's Breech

It forms a robust, non-spiny clump

• Flowering time July to September
• Height at maturity 1,50 m

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Acanthus spinosus - Bear's Breech

It develops highly decorative spiny foliage and produces spectacular summer flower spikes!

• Flowering time July to September
• Height at maturity 1 m

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Acanthus hungaricus

We love the lushness of its deeply lobed, glossy green leaves without spines

• Flowering time July, August
• Height at maturity 80 cm

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Acanthus mollis Rue Ledan - Bear's Breech

An easy-to-grow ornamental giant

• Flowering time July, August
• Height at maturity 1,20 m

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Acanthus mollis Hollards Gold - Bear's Breech

A luminous Acanthus with abundant white flowers and golden-yellow foliage

• Flowering time July to September
• Height at maturity 80 cm

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Planting

Where to Plant Acanthus?

Acanthus thrives easily in full sun, where it will grow taller and produce more flowers, but it can tolerate light shade during the hottest hours in regions south of the Loire. This hardy perennial can be planted throughout France. Most varieties are vigorous and can withstand temperatures as low as -15°C for short periods, though some species may be more frost-sensitive.

While it grows in all types of soil, provided it is very well-drained, even dry or stony, and cool in summer, it prefers rich, deep soils. It only dislikes waterlogged or soggy soils in winter. In heavy, wet soil, it will struggle, grow slowly, or die. Ensure it is planted with its roots in a dry spot, free from excess winter moisture. On the other hand, this Mediterranean plant tolerates summer drought well.

Acanthus is a plant that values stability and dislikes being moved, so choose its planting location carefully and allow ample space for growth.

Highly architectural, it is ideal for adding height and volume to perennial borders. It fits into all types of settings, flower beds or borders, but truly shines as a mid-border or backdrop plant. The spiny Acanthus, or A. spinosus, forms a robust ground cover on challenging slopes. Other varieties create a spectacular focal point in large perennial beds, as a standalone feature on a lawn, or planted in groups at the edge of a woodland.

Large species need plenty of space, as they tend to smother delicate neighbouring plants. They prefer a sunny, sheltered spot, free from strong winds, which encourages them to reach their full height. Plant them at the back of borders to add dramatic structure and vertical interest.

Container cultivation is not recommended for these plants, which prefer cool, deep soil, though it is possible with some precautions. More so than in the ground, potted Acanthus requires fertiliser and sun, in a container at least 30 cm deep, filled with enriched compost or well-rotted manure.

Acanthus spreads via rhizomes, naturalising easily where conditions suit it, whether in full sun, partial shade, or even shade.

When to Plant?

Ideally, in spring, April or May, depending on the region, once the risk of frost has passed. Autumn planting is also possible to encourage root establishment before winter.

How to Plant Acanthus?

Plant in deep, cool soil, not overly chalky, rich and well-drained. Be cautious—this plant is spiky; the leaf edges often bear sharp spines that can cause injury.

In heavy, clay soil, add compost and potting mix at planting time, lightening it with river sand or pumice to prevent excess moisture, which Acanthus dislikes. Space plants about 60-80 cm apart to allow for proper growth.

• Keep the rootball intact, as Acanthus roots dislike disturbance
• Dig a hole 3 to 5 times wider than the rootball and deep
• Backfill soil around the roots and firm gently
• Water thoroughly until established
• Protect from slugs
• Mulch, especially in the first winter after planting, to aid establishment, retain summer moisture, and guard against late frosts
• During growth, water moderately—keep the soil cool in summer but never waterlogged
• Apply liquid fertiliser once a month

Note: In summer, the plant enters dormancy and its foliage yellows—avoid overwatering, as this is part of its natural cycle to withstand drought.

Maintenance, Pruning and Care

Once well established, Acanthus requires no special care. It doesn’t need watering except during prolonged drought.

After flowering and before fruiting, cut back the flower stems if you wish to prevent self-seeding or leave them to set seed for natural propagation, then cut back the faded foliage in autumn.

Although hardy, it may struggle with intense cold, especially during prolonged deep frosts. You can leave the cut foliage in place as a natural mulch during very cold weather to prevent frost damage. Repeat this in summer with a mulch of dried leaves, for example, to maintain soil moisture.

In summer, reduce watering during dormancy – the foliage disappears in extreme heat but will regrow from the base in autumn.

Diseases and potential pests

The Bear’s Breeches has two known enemies:

• Snails and slugs that devour young shoots before they even emerge from the ground in spring. Mechanical traps or slug pellets, applied at planting time, then annually from February onwards, are essential.
• Powdery mildew, recognisable by the white felt-like coating it leaves on leaves. If needed, spray preventatively with nettle and horsetail manure.

Propagation

Perfectly at home in your garden, Bear’s Breeches will self-seed spontaneously. However, it can also be easily propagated by seed or root cuttings. We do not recommend dividing clumps, as this is too risky – Bear’s Breeches dislikes being disturbed.

By seed

You can sow directly in the ground or under a cold frame in March, using seeds harvested in autumn when ripe, before the seed pods burst and scatter their contents. When propagating Bear’s Breeches, the first flowers will only appear after 2-3 years. Seed-grown plants rarely resemble the parent plant.

• Direct sowing

Thin out seedlings as they begin to develop

• In a greenhouse

Sow in spring on compost, barely covering with moist potting mix. Germination takes one to four weeks. Transplant seedlings as soon as the first leaves appear, planting them directly in their final position.

→ Learn more with our tutorial: How to harvest and sow Bear’s Breeches seeds?

By root cuttings

Root cuttings guarantee robust plants with the same colour as the parent plant. This method should be done on plants aged 3 or 4 years.

• In autumn or late winter, carefully dig up roots with a garden fork
• Cut them into 5 to 8 cm sections
• Insert them horizontally into pots containing a light, well-draining mix of sandy compost, just covering them
• Maintain at 15 to 20°C and water regularly
• Root formation takes four to five weeks
• Transplant into pots or plant directly in the ground

→ Learn more in our tutorial: How to propagate Bear’s Breeches?

Pair

Bear’s Breech is a striking perennial that adds a much sought-after architectural touch to gardens. With its highly graphic form, it brings panache, volume and verticality to perennial or annual borders.

A reliable choice for herbaceous borders, it is prized for its imposing spikes of white, pink or yellow flowers. It pairs beautifully with the mauve-pink blooms of Lavatera, while purple-flowered varieties create striking contrasts with the yellow flowers of golden camomile or the green-yellow inflorescences of Lady’s Mantle.

In natural gardens, pair Acanthus spinosus with Pennisetum orientale ‘Karley Rose’, Allium sphaerocephalon and Salvia nemorosa ‘Caradonna’

Typically flowering during rose season in late spring and early summer, it makes an excellent companion for white or yellow heritage or repeat-flowering roses, creating charming, romantic displays alongside numerous other sun-loving perennials.

It suits all garden styles, and with its generous, deeply cut foliage, can play either the striking role of a focal plant at the back of borders or serve as a bedding plant.

Its tall, highly structural silhouette brings movement to prairie-style gardens, natural woodland edge plantings, or more contemporary schemes.

It’s also a must-have for white gardens, where it thrives alongside white-flowered roses, Echinacea ‘Meringue’, Digitalis ‘Snow Thimble’ or Epilobium angustifolium album.

Digitalis ‘Snow Thimble’, Echinacea purpurea ‘Meringue’, Epilobium angustifolium album and variegated foliage of Acanthus ‘Whitewater’

It combines beautifully in opulent, somewhat exotic summer displays with echinaceas, giant sea hollies, Cimicifuga racemosa, red hot pokers or giant dahlias. Its spectacular foliage and summer flower spikes complement Oriental poppies perfectly.

In dry gardens, it adds panache alongside yarrows, agastaches, artemisias, Ceratostigma griffithii, or euphorbias.

The plant combines particularly well with softer-foliaged plants like ornamental grasses, creating delightful textural contrasts.

→ Discover more Bear’s Breech planting ideas in Gwenaëlle’s advice sheet