Acanthus mollis, which is also known as the Oyster Plant as well as ‘Bear’s Breeches’, and the related Acanthus spinosa (see picture at right) are two of the best known species available for sale in Australia.
This is a clump-forming perennial plant that develops into a dense clump. Valued for its bold architectural foliage and tall flower spikes, Acanthus mollis is a popular choice for cottage gardens, Mediterranean-style gardens and shaded borders.
Masses of low-growing deep green glossy foliage are topped by tall spires of flowers that rise above the leaves from spring into summer.
A small clump will easily cover 1 metre and, when planted beneath deciduous trees, Acanthus mollis can make an excellent ground cover. Once established it is also useful for suppressing weeds beneath trees and in difficult dry shade situations.
his plant does have its problems, mainly in that it will self-seed. However, deadheading can take care of that. Just remember to dispose of the seed heads. The plant can also spread slowly from underground roots, so allow sufficient room when planting.
Quick Facts
- Botanical Name: Acanthus mollis
- Common Names: Bear’s Breeches, Oyster Plant
- Plant Type: Herbaceous perennial
- Height: 1–1.5 metres
- Spread: 1–1.5 metres
- Foliage: Deep green, glossy, deeply lobed leaves
- Flowers: White with purple bracts
- Flowering Time: Late spring to summer
- Position: Full sun to part shade
- Soil: Fertile, well-drained soil
- Drought Tolerance: Moderate once established
- Suitable For: Cottage gardens, Mediterranean gardens, shaded borders, underplanting beneath deciduous trees
- Maintenance: Low, remove spent flower spikes to prevent self-seeding
How to grow Acanthus mollis – Basic Care
Acanthus mollis is a fairly vigorous herbaceous perennial flowering from late spring through to early summer. Large dark glossy green leaves are a feature, and the only issue you may have is with snails eating young plants. The deeply lobed foliage provides interest for much of the year, even when the plant is not in flower.
Although often sold as evergreen, in Australia it may die back during particularly hot summers. In cooler climates it will usually retain foliage year round.
Acanthus mollis or ‘Bear’s Breeches’ grows to around 1 metre in height and forms an upright clump. It is an excellent foliage plant beneath trees and in shaded garden beds. The distinctive white and purple flowers rise well above the foliage on tall stems.
Best growth is achieved in fertile, well-drained soil in part shade, although established plants will tolerate periods of drought and full sun in cooler climates.
Acanthus combines well with Hostas, Clivia, Agapanthus, Hellebores and ornamental grasses where contrasting foliage textures are desired.
Look for other species including A. spinosa, or ‘Spiny Bear’s Breeches’, and A. caroli-alexandri, an interesting form with deeply cut spiky foliage. This is a great texture plant for mixed borders and foliage gardens.
Where To Buy
Acanthus plants are available for sale from the following nurseries
52 Rodd St Canowindra NSW 2804
An online nursery specialising in drought and frost tolerant perennials and fragrant, edible and herbs.
www.perennialle.com.au
Large variety of Epimediums, Woodland plants and Herbaceous perennials
Mail order or nursery. We do not send to Tasmania or WA
www.cloverhillrareplants.com
'Umbango' 750 Humula Rd, Humula NSW 2652
Phone 0408692773 Great Range of Perennial plants available for sale by mail order.
www.nutshellnursery.com.au
125 Palmer Rd Jindivick 3818
Open Thursday - Sunday 10am - 4pm
Specialising in growing and selling Rare and Unusual Trees, shrubs Perennials Bulbs and Climbers, a unique nursery with amazing stock.
www.muskersbroughtonhall.com.au
412 James Lane, Fern Hill VIC. 3458 - Phone 0419002651
Large range of Rare plants, Climbers, Bulbs, Perennials Fruit Trees, Ornamental Trees and Shrubs. Available both Retail and by Mail Order
www.whitehousenursery.com.au
Frequently Asked Questions
Is Acanthus mollis invasive?
Acanthus mollis can spread over time through both self-seeding and underground roots. In larger gardens this is rarely a problem, however in smaller garden beds it is worth allowing sufficient space for the plant to develop. Removing spent flower spikes will help prevent unwanted seedlings.
Does Acanthus mollis grow in shade?
Yes. Acanthus mollis grows well in part shade and is particularly useful beneath deciduous trees where it receives winter sun and summer shade. It will also tolerate full sun in cooler climates provided adequate moisture is available.
Is Acanthus mollis evergreen?
In cooler climates Acanthus mollis is often evergreen and retains its attractive foliage throughout the year. In hotter regions and during prolonged dry periods it may die back and re-emerge when conditions improve.
How tall does Acanthus mollis grow?
Flower spikes typically reach between 1 and 1.5 metres in height, while the foliage clump usually grows to around 60 cm high and can spread to over 1 metre wide.
Is Acanthus mollis drought tolerant?
Once established, Acanthus mollis is reasonably drought tolerant. However, it performs best in fertile soil with occasional deep watering during extended dry periods.
Can Acanthus mollis be grown in containers?
Acanthus mollis can be grown in large containers, although it is generally better suited to garden beds where it has room to develop its extensive root system and large foliage clump.