Berkheya purpurea (DC.) Mast.

Kew Species Profiles

General Description

Purple berkheya is the only mauve to purple flowered species in the genus, most of the others being yellow or in some cases white.

There are about 75 species of Berkheya, a genus of shrubs and perennials distributed throughout tropical Africa, and named after the Dutch botanist Jan le Francq van Berkhey (1729-1812) by the German botanist Jakob Friedrich Ehrhart in 1788. Over 70 species are native to South Africa, where they grow mainly on mountain slopes.

Berkheya purpurea is the only mauve to purple flowered species in the genus (most are yellow or occasionally white), and was first described in 1838 by the French botanist Augustin Pyramus de Candolle, who named it Stobaea purpurea. It was renamed Berkheya purpurea in 1872.

Species Profile

Geography and distribution

Berkheya purpurea is found in South Africa at 1,500-3,000 m above sea level, from the mountains of the Eastern Cape to the Drakensberg in KwaZulu-Natal and also in Lesotho and Orange Free State.

Description

Overview:   Berkheya purpurea is a rhizomatous perennial forming a dense prickly rosette of foliage.

Leaves: The leaves measure 25-45 cm long and 4-10 cm wide and are green on the upper side, downy on the underside with spiny margins.

Flowers: The single flowering stem, up to 1 m high, appears from December to April in the wild and June to August in cultivation. The flower heads (capitula) are carried on short side branches on the upper part of the flowering stalk, and the buds open in succession from the top of the stem downwards. Several capitula may open simultaneously. Each capitulum has a ring of pale mauve outer ray florets with central dark purple disc florets, although occasionally the ray florets may be white. A circle of spiny green bracts (phyllaries) protects the capitula.

Fruits: The pappus (scales surrounding the apex of the fruit) is light green at first and then turns light to dark brown as the fruits (achenes) mature.

The flowers are pollinated by bees.

Uses

Purple berkheya is cultivated as an ornamental.

Cultivation

Berkheya purpurea was apparently grown at Kew around 1917 but has only recently become popular in gardens in Britain; it is now available from commercial seed companies.

In Britain, plants raised from seed (ideally sown after collecting in the autumn or delayed until the following spring) are planted out in the garden in spring. They grow best in well-drained soil and full sun. They look good in groups and planted among low grasses, as seen in the wild.

Berkheya purpurea is also propagated by division of the rootstock.

This species at Kew

Purple berkheya can be seen growing in the Rock Garden at Kew, and in the South African Bed of the Southern Hemisphere Garden at Wakehurst.

Pressed and dried, and alcohol-preserved specimens of Berkheya purpurea are held in Kew's Herbarium, where they are available to researchers from around the world, by appointment. The details of some of these specimens, including images, can be seen online in the Herbarium Catalogue.

Distribution

South Africa

Ecology

Beside streams and on steep, grassy mountain slopes.

Conservation

Least Concern (LC) according to Red List of South African Plants 2009, following IUCN Red List criteria.

Hazards

Spiny leaves.

Use

Ornamental.