Overview

Onopordon acanthium is a biennial in the genus Onopordon, part of the Asteraceae family. Onopordon acanthium grows best in full sun, and tolerates most soils and neutral and alkaline pH. Its UK hardiness is rated H5. Suggested uses include wildlife gardens, naturalized areas and erosion control. It is native to Europe, Western Asia and North Africa.

About

Onopordon acanthium, the Cotton Thistle, is a biennial or short-lived perennial thistle in the Asteraceae. It favours full sun and well-drained sandy or loamy soils with neutral to alkaline pH. The plant suits exposed, south-facing positions and tolerates dry to medium soil moisture. Classified H5, it is regarded as hardy in typical UK gardens.

About the genus

Onopordum, or cottonthistle, is a genus of plants in the tribe Cardueae within the family Asteraceae. They are native to southern Europe, northern Africa, the Canary Islands, the Caucasus, and southwest and central Asia.

In the garden

Onopordon acanthium is a thistle native to Europe, Western Asia and North Africa and belongs to the Asteraceae. Plants follow a biennial or occasionally short-lived perennial habit, establishing before producing their second-year growth, and are best located where they receive uninterrupted sun. Choose a very sunny, south-facing site with good drainage; sandy or loamy soils on neutral to alkaline pH suit it best. It tolerates dry to medium soil moisture and performs well in exposed spots where shelter is limited. Its hardiness rating H5 indicates it is hardy across much of the UK and will survive typical winter conditions. In a British garden it is most useful in wildlife schemes, naturalised margins and on banks where erosion control is required. Position specimens where they will not crowd finer plants and where full sun and exposure are available. Allowing Cotton Thistle to occupy tougher, open ground makes the most of its preference for dry, south-facing sites and contributes to erosion control and wildlife value specific to this species.

Growing conditions

Best soil and position for Onopordon

Sunlight

full sun

Soil type

well-drained, sandy, loamy

Soil pH

neutral, alkaline

Soil moisture

dry to medium

Aspect

south-facing

Exposure

exposed

UK hardiness

H5

Plant details

Onopordon acanthium size, habit and characteristics

Plant type

biennial, perennial

Suggested uses

wildlife gardens, naturalized areas, erosion control

Native to

Europe, Western Asia, North Africa

Care notes

Pruning and caring for Onopordon acanthium

Cultivation

Prefers dry, well-drained soils in full sun; tolerates poor soils; avoid waterlogging.

Pruning

Remove flower heads before seed set to prevent self-seeding; cut back after flowering.

Propagation

Seed

Frequently asked questions