Epimedium sagittatum Seeds | Barrenwort
LATIN NAME: Epimedium sagittatum
COMMON NAME: Barrenwort
Plant Profile
Barrenwort is a low, clumping perennial that spreads slowly by a woody, creeping rootstock, sending up wiry stems thirty to sixty centimetres tall. The leaves are the identifying feature: each is divided into three leaflets, and each leaflet is arrow-shaped, with two long basal lobes pointing back down the stalk, a wavy, spine-toothed margin and a leathery, semi-evergreen texture. New foliage in spring is bronze or red, turning dark green for summer, and old leaves persist through winter until they are cut back.
The flowers appear in loose, airy sprays in mid-spring, each one small and pale yellow, with four petals folded into a short curved spur and four showy sepals that drop as the flower opens. They are held above the foliage on thin, reddish stems, and they move in the slightest breeze. The fruit is a small follicle that splits to release a few seed with a fleshy appendage, which ants carry away. The species is native to the forests of southern and central China, from Zhejiang and Fujian across to Sichuan and Guizhou, growing in shade on humus-rich, well-drained slopes between two hundred and fifteen hundred metres. It is one of several epimediums collected as Yin Yang Huo, and the group is notoriously difficult to tell apart without flowers.
Science & Biotechnology
The medicinal chemistry of Epimedium is dominated by icariin and the related prenylflavonoids epimedin A, B and C, which occur in the leaves and stems and are extracted commercially. Icariin is metabolised to icariside II, and that compound inhibits phosphodiesterase-5, the same enzyme targeted by prescription drugs for erectile dysfunction, which explains much of the plant’s reputation. The flavonoids also stimulate osteoblast activity and inhibit osteoclast formation in cell and animal models, and they bind to oestrogen receptors, which has made the plant a subject of research into bone loss after menopause.
Pharmacological work on the species is complicated by the fact that the raw material in trade is a mixture. The Chinese pharmacopoeia recognises several Epimedium species as sources of Yin Yang Huo, including this one, and the icariin content varies widely between them and with the season and the plant part used. HPLC fingerprinting and DNA barcoding are now used to authenticate batches, and studies have shown that a significant proportion of commercial material is misidentified or adulterated. There is also a safety literature: high doses of icariin have produced liver enzyme changes in some users, and the herb is not recommended for children or during pregnancy. The botanical side of the research covers the genus’s hybrid complexes, its chromosome numbers and its unusual floral morphology, in which the petals are modified into nectar-bearing spurs.
Uses & Benefits
Yin Yang Huo is one of the warmer tonics in Chinese medicine, used for what the tradition calls kidney yang deficiency: cold limbs, low back pain, frequency of urination and diminished sexual function. It is normally prescribed in a formula with other herbs rather than taken alone, and the dose is modest. The modern supplement market has taken the plant up as a natural alternative to prescription drugs, which is a development worth treating with caution, since the active compounds are pharmacologically potent and interact with nitrates and with blood pressure medication.
In the garden, barrenwort is one of the best ground covers for dry shade under deciduous trees. It competes well with tree roots, tolerates drought once established, and its spring flowers and bronze new foliage give two seasons of interest in a place where little else will grow. It is also a useful plant for the front of a woodland border, for a shaded rock garden, or for underplanting shrubs. The foliage remains semi-evergreen in mild winters and should be cut back in late winter, before the flower spikes emerge, to keep the clump tidy.
Growing from Seed
The seed is short-lived and should be sown fresh, as soon as the follicles split in early summer. Clean off the fleshy appendage, sow on the surface of a mix of leaf mould, coarse sand and loam, and cover very lightly. Keep the tray shaded, cool and constantly moist; germination takes four to eight weeks, and the seedlings are slow for their first year. Seed that has been dried and stored usually fails, which is why division is the usual method of increase.
Divide established clumps in early autumn or immediately after flowering, when the plant is not in full growth. Lift the rootstock, cut it into sections each with two or three buds and a good set of roots, and replant at the same depth in humus-rich soil. Water well and mulch with leaf mould. Space the divisions thirty centimetres apart; they will close the gap in two seasons. The plant prefers shade or part shade, and it tolerates dry soil once the rootstock is established, though it flowers best with steady moisture in spring.
Our Take
A first-rate shade plant and a medicinal herb in one, though the two uses should be kept separate. Grow it for the spring flowers and the ground cover, and leave the medicine to those who know the dose.
Related Reading
Continue exploring with these related plants: