Common name : Oyster Plant, Bear’s Breeches
Family : Acanthaceae
Acanthus mollis is a plant I very often incorporate into my gardens.
It is easy to grow, creates a good shape in the border and provides interest through both its foliage and its flowers.
It is a clump forming, evergreen soft-wooded perennial with an architectural habit. It grows to 1.8m x 1.5m.
It has many large (up to 1m in length) glossy, dark green lobed leaves and produces a tall spike of purple, green and white flowers with spiny bracts.
Use it as a robust, lush ground cover in shade or as a feature plant in mixed borders. Its dark and glossy foliage provides a foil for many flowering plants.
Interestingly, the leaves of this striking plant are the ones used as on the friezes and columns of classical Greek architecture.
Acanthus mollis should be grown in full to partial shade in hot climates.
Full sun may encourage flowering but where heat is intense, it is likely to produce leaf scorch.
In more temperate climates it can be grown in full sun or partial shade.
It will grow in any fertile, well drained soil but prefers a deep loam. It is frost hardy to -15 degrees C and is moderately drought tolerant when established.
Pruning is only necessary to remove spent flowers and old leaves.
Water well to establish and mulch well to maintain moisture in the soil. Apply a general purpose fertiliser twice a year.
Be aware that it can be a bit ‘weedy’ because, once established, Acanthus mollis is very hard to remove.
It roots deeply and if you dig it up, you will almost certainly find that it re-grows from scraps of roots that are left behind
Pests and diseases
Can suffer the attentions of slugs and snails and also be troubled by powdery mildew.
By seed, division in spring or autumn or by taking root cuttings in winter.
Brickell C (ed), 1998, the Royal Horticultural Society A to Z Encyclopedia of Garden Plants Dorling Kindersley, London.
Rice G (ed), 2006, the Royal Horticultural Society Encyclopedia of Perennials, Dorling Kindersley, London.
Rowell R, 1991, Ornamental Flowering Plants in Australia, University of New South Wales Press, NSW.