Why this delicate garden flower is better known as horny goat weed

Cultures · Published 10 October 2026 · Updated 25 October 2026 Swipe more like this →

In short: Known in gardens as bishop's hat or fairy wings, the Epimedium genus hides a surprising reputation. While gardeners prize its heart-shaped leaves and star-like spring blooms, the plant is also marketed as a sexual health supplement, thanks to a chemical compound that mimics the mechanism of modern prescription drugs.

The genus Epimedium, comprising hardy perennials in the Berberidaceae family, is primarily native to China, though species also appear across Asia and the Mediterranean. Named by Carl Linnaeus in 1753, the plant is characterized by its underground rhizomes and distinctive four-parted flowers. These blooms often feature complex, nectar-producing spurs, which inspired the common name bishop's hat. Gardeners value these plants as versatile groundcover, thriving in conditions ranging from dappled to deep shade.

Beyond the garden, the species Epimedium grandiflorum has gained notoriety as a dietary supplement. It contains a compound called icariin, which functions in vitro as a weak PDE5 inhibitor. Because drugs like sildenafil, vardenafil, and tadalafil—sold as Viagra, Levitra, and Cialis—rely on stronger PDE5 inhibitory action to treat erectile dysfunction, the plant is frequently included in men's sexual health products. However, clinical evidence for these effects in humans remains limited, and the actual clinical impact of the plant is currently unknown.

The horticultural world has seen a surge in interest, with breeders like Darrell Diano Probst, Tim Branney, and Robin White developing new hybrids. While early assumptions suggested these plants required specific native conditions, many varieties have proven remarkably adaptable to general garden and container cultivation. Recent exploration has introduced a wide array of new Chinese species to Western gardens, many of which are still being categorized and tested for hardiness. Meanwhile, research into the chemical makeup of species like Epimedium wushanense continues, with scientists identifying dozens of compounds, including prenylflavonoids like epimedin C, which can make up over 5% of the plant's aerial parts.

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