Epimedium and its Cultivation

Epimedium also known as barrenwort, bishop's hat, fairy wings, horny goat weed, or Yin Yang Huo (Chinese: Epimedium; Pinyin: Yínyánghùo; Wade–Giles: Yin⊃2;-yang⊃2;-huo⁴), is a flowering plant Berberidaceae.Most species are endemic to China, with smaller numbers elsewhere in Asia and some in the Mediterranean region.Epimedium is a deciduous or evergreen hardy perennial. Most produce four-lobed "spider-like" flowers in spring.The species used as a dietary supplement is Epimedium.It contains icariin, which is a weak PDE5 inhibitor in vitro. Its clinical effects are unknown.There is little clinical evidence, but it is thought to have erectile-promoting properties and is found in some male sexual health supplements.

Descriptions 

Epimedium is a perennial herb that grows from underground rhizomes.Their growth habits are somewhat variable.Some have solitary stems, while others have a "clump" habit, with multiple stems growing together.A single stem may have several leaves, or the leaves may be solitary, arising from the base of the plant.The single leaves are generally compound, often with three leaflets, but there are more.Leaflets often have spiny edges.The leaves may be annual, making the plant deciduous, or more permanent so the plant is evergreen.Inflorescences are open racemes or panicles, the number of flowers varying by species.A single flower divides into four petals.There are four smaller outer sepals, which are usually green in color and fall off when the flowers open.Moving inward, they are followed by four larger petal-like inner sepals, often brightly colored.There are four true petals inside the sepals.These may be small and flat, but often have complex shapes, including nectar-producing "thorns" that may be longer than the sepals.There are four stamens.One of the common names for the genus, bishop's cap, derives from the shape of the flowers, especially where the spur is longer than the sepals.

Cultivations

Several varieties and hybrids have been grown in the West for the past 100 to 150 years. A large number of new Chinese species are now being bred in the West, many of which have only recently been discovered and some have yet to be named.There are also many older Japanese hybrids and forms that stretch the boundaries of the cultivated genus.Most Chinese species have not been adequately tested for hardiness or any other cultural aspect. As it turns out, it was overly cautious to initially assume that plants would only thrive where their native conditions could be closely replicated, as most varieties have proven to be well suited to general gardens and container growing.

Propagation

While they can propagate successfully in early spring, epimedium is best divided in late summer to promote rapid regrowth of roots and shoots before winter sets in.Some breeders (notably Darrell Diano Probst, Tim Branney, and Robin White) have also developed their own hybridization programs with this genus.Various new nursery options are gradually appearing in the gardening industry, the best of which expand the range of colors and shapes of flowers available to gardeners.