Epimedium perralderianum (barrenwort)

Native to north-eastern Algeria, where it grows in the oak and cedar forests of Mount Babor, at 1,200–1,500 m above sea level.

Epimedium perralderianum is one of the interesting species found in the relicts of moist forest in the North African mountains. The closely related E. pinnatum subspecies colchicum grows in the moist forests of the Black Sea coast in north-eastern Turkey. Mount Babor (Djebel Babor) in Algeria is one of the wettest places in North Africa (with 2,000–2,500 mm average annual rainfall). It contains the last remnants of forests which covered much of North Africa during the glacial maximum 20,000 years ago. Oaks, holly, yew, aspen and Acer opalus subsp. obtusatum are all found here, along with Atlas cedar (Cedrus atlantica), which occurs from around 1,200 m above sea level in mixed woodland, and dominates at higher altitudes (above 1,800 m). Part of the area is protected as the Djebel Babor Strict Nature Reserve.

The long-creeping rhizome (underground stem) is tough and wiry. The leaves are up to 20 cm long and are divided into three leaflets, each up to 6.5 cm long (or up to 10 cm in cultivation). The glandular flowering stems are up to 30 cm high and bear 9–25 flowers. The flowers are 1.5–2.3 cm across, and each has four small, greenish outer sepals and four large, yellow inner sepals 5–9 mm across. Each flower has four small (2.5 mm long) petals, with small, brown nectaries with an upward-curving spur 1–2 mm long. The stamens (male parts) are 5 mm long and bear yellow anthers (pollen-bearing structures).

Hand-coloured lithograph of Epimedium perralderianum after a painting by Harriet Thistleton-Dyer (1880), taken from Curtis's Botanical Magazine (Image: RBG Kew)

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Epimedium perralderianum was listed as Vulnerable according to IUCN Red List criteria in 1998. It has a very restricted distribution in the wild, and is likely to be adversely affected by any deforestation.

Epimedium perralderianum is cultivated as an ornamental. It makes a good groundcover plant for moist, partially shaded places (such as in a woodland garden). Its leaves turn red in late summer and autumn.

Some Chinese species of Epimedium are used medicinally. For example, E. sagittatum is one of four source species of the Traditional Chinese Medicine (TCM) called ‘Yin Yang Huo’ (pharmaceutical name: Herba Epimedii). The aerial parts of the plant are used to treat impotence, rheumatoid arthritis, numbness and muscle contractions, and hypertension during menopause, among other conditions.

Epimedium perralderianum is easily grown in partial shade, preferably in places which do not dry out in summer. It can be propagated easily by division.

Epimedium perralderianum is grown in the Woodland Garden (the area around the Temple of Aeolus) at Kew.

Dried and alcohol-preserved specimens of Epimedium perralderianum are held in Kew’s Herbarium, where they are available to researchers from around the world, by appointment. The details of one of these specimens can be seen online in the Herbarium Catalogue.

Search Kew's databases for more information on this species

Curtis’s Botanical Magazine (Wiley-Blackwell)

The Telegraph – How to grow: Epimedium perralderianum