Acanthus spinosus

How to grow acanthus

Find out all you need to know about growing acanthus, or bear's breeches, in this detailed Grow Guide.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Plant
Plant

Do not Plant in January

Do not Plant in February

Do not Plant in March

Do Plant in April

Do Plant in May

Do not Plant in June

Do not Plant in July

Do not Plant in August

Do Plant in September

Do Plant in October

Do not Plant in November

Do not Plant in December

Flowers
Flowers

Plant does not flower in January

Plant does not flower in February

Plant does not flower in March

Plant does not flower in April

Plant does flower in May

Plant does flower in June

Plant does flower in July

Plant does flower in August

Plant does not flower in September

Plant does not flower in October

Plant does not flower in November

Plant does not flower in December

Cut back
Cut back

Do not Cut back in January

Do not Cut back in February

Do Cut back in March

Do not Cut back in April

Do not Cut back in May

Do not Cut back in June

Do not Cut back in July

Do not Cut back in August

Do Cut back in September

Do Cut back in October

Do not Cut back in November

Do not Cut back in December

Acanthus are bold plants, with evergreen architectural foliage and tall flower spikes in summer.

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They suit bold planting schemes, and look best placed toward the front of a border, where the large, glossy leaves are on show, or, if space allows, planted in large groups. The Romans used Acanthus spinosus leaves as the inspiration for the decorative details on classic Corinthian columns. Also known as bear’s britches, acanthus flowers are very distinctive with white outer petals appearing from under a purple hooded leaf bract. Bees love them. They make good cut flowers and can be used in fresh and dried arrangements.

More Grow Guides:

Take a look at our handy acanthus Grow Guide, below.


Where to grow acanthus

A native of Mediterranean countries, acanthus prefers moist but well-drained soil in full sun to partial shade. But make sure you choose the correct position as, once established, with a large tap root, plants aren’t easy to move.


Planting acanthus

Acanthus mollis
Acanthus mollis

Plant in spring or autumn. Dig a generous hole, adding a spadeful of well rotted manure to help the plant establish.


Propagating acanthus

Collecting seeds from Acanthus mollis
Collecting seeds from Acanthus mollis

Although acanthus plants are large and not easy to dig up, they can be propagated by root cuttings to increase your stock or replace old plants. In spring, dig up the whole plant and split the root with a spade and pot up sections of root in compost to grown on before planting out. They can be grown from seed, but need plenty of warmth to germinate.


Acanthus: problem solving

The large leaves of acanthus are very prone to powdery mildew in dry weather, so make sure that plants are kept well-watered.


Caring for acanthus

Dried acanthus stems
Dried acanthus stems

Cut back stems after flowering, and tidy foliage in spring. If clumps are congested, divide them in spring or autumn.


Acanthus varieties to grow

Acanthus spinosus
Acanthus spinosus flowers
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  • ‘Summer Beauty’ – a hybrid, forming wide clumps of giant, glossy, dark green, finely cut foliage. In summer tall spikes of white flowers, each with a hood-like purple bract, appear. It’s perfect for growing in a mixed herbaceous border, particularly among bold colours
  • Acanthus spinosus – a statuesque architectural plant, that brings classical elegance to the garden. The leaves are smaller and more finely cut than Acanthus mollis, with spiny tips, but the plant produces more flower spikes. The Royal Horticultural Society has given it the prestigious Award of Garden Merit (AGM)
  • ‘Whitewater’ – dark green leaves splashed with white, with bold margins. Its flowers are pink and cream-white. It’s perfect for growing in a mixed herbaceous border, particularly among bold colours, and makes striking architectural presence