Epimedium

Basic Information

Common Name: Epimedium

Scientific Name: Epimedium

Native Habitat: Primarily found in woodlands and forests of East Asia, especially China, Korea, and Japan. Some species also occur in Southern Europe.

History / Discovery / Cultivator

Epimediums, commonly known as barrenworts, have a long and fascinating history, deeply intertwined with traditional medicine and garden cultivation. Their association with Eastern cultures, particularly China, dates back centuries. The plant’s use in traditional Chinese medicine (TCM) is well-documented, with the herb known as “Yin Yang Huo,” translating to “licentious goat wort” or “horny goat weed.” Legend has it that a goat herder noticed increased sexual activity in his flock after they consumed the plant. This observation led to the herb’s use as an aphrodisiac and to treat various ailments related to kidney yang deficiency, such as fatigue, joint pain, and impotence.

The formal botanical classification and study of Epimedium lagged behind its traditional use. While species were recognized earlier, the taxonomic work to differentiate and categorize the many varieties continues today. Western botanists were introduced to Epimediums through plant explorations in East Asia, primarily during the 19th and 20th centuries. Plant collectors and botanists like Robert Fortune, Ernest Henry Wilson, and Frank Kingdon-Ward played significant roles in bringing new species of Epimedium to Western gardens. These intrepid explorers ventured into remote regions of China, Korea, and Japan, collecting plant specimens and seeds, which were then introduced to botanical gardens and private collections in Europe and North America.

Early cultivation efforts focused on establishing the plants in woodland gardens, where their tolerance of dry shade made them valuable groundcover options. Over time, breeders and horticulturists began to appreciate the diversity of Epimedium, recognizing the variations in leaf shape, flower color, and growth habit. This sparked an interest in hybridization and the development of new cultivars. Darrell Probst is a contemporary figure known for his extensive work with Epimediums. His contributions involve the introduction of numerous hybrids and species, many of which exhibit unique characteristics and improved garden performance. He has meticulously collected and studied Epimediums, contributing significantly to our understanding and appreciation of the genus. Another notable cultivator is Robin White, whose Blackthorn Nursery has been instrumental in popularizing many Epimedium varieties. The cultivation of Epimedium has shifted from primarily a groundcover plant to a highly sought-after genus with specialized cultivars.

The geographical origins of Epimedium are predominantly East Asian, with China being the center of diversity. However, some species are native to Southern Europe, adding to the geographical spread of the genus. The introduction of Epimediums to Western gardens has transformed these once relatively obscure woodland plants into highly prized ornamentals, celebrated for their resilience, beauty, and unique history.

Plant Care Summary

Botanical Insights

Adaptations

Epimediums exhibit several notable adaptations that contribute to their survival and success in their native woodland environments. Their rhizomatous root systems enable them to spread and form dense groundcovers, effectively competing with other plants for resources. This spreading habit also allows them to colonize areas with varying levels of light and moisture. The foliage of many Epimedium species is semi-evergreen or evergreen, providing year-round ground cover and helping to suppress weed growth. Their tolerance of dry shade is particularly advantageous, as it allows them to thrive in areas where many other plants struggle. The unique spurred flowers of Epimediums are adapted for pollination by specialized insects, such as bees and flies. The spurs contain nectar, attracting pollinators and ensuring successful reproduction. The leaves are often waxy or leathery, reducing water loss and helping them withstand periods of drought. Some species also exhibit colorful new growth in the spring, providing camouflage to protect against herbivores.

Propagation Methods

Epimediums can be propagated through several methods, including:

• Division: This is the easiest and most common method. Divide established clumps in early spring or fall. Ensure each division has healthy rhizomes and foliage.
• Seed: Epimediums can be grown from seed, but it is a slower process and may not result in plants that are true to type. Seeds should be sown fresh in a well-draining medium and kept moist.
• Rhizome Cuttings: Sections of rhizome with buds can be taken and rooted in a moist medium. This method is useful for propagating specific cultivars or hybrids.

Toxicology

Epimediums contain compounds that can cause mild toxicity if ingested. The primary concern is the presence of icariin, a flavonoid that has various pharmacological effects. In humans, consuming large quantities of Epimedium can cause gastrointestinal upset, including nausea, vomiting, and diarrhea. In rare cases, it may also lead to rapid or irregular heartbeat. For pets like cats and dogs, ingestion of Epimedium can result in similar symptoms, such as vomiting, diarrhea, and loss of appetite. The severity of the reaction depends on the amount ingested and the size of the animal. While not considered highly toxic, it is advisable to keep Epimediums out of reach of children and pets to prevent accidental ingestion. If ingestion occurs, monitoring for symptoms and contacting a veterinarian or medical professional is recommended.

Common Problems

Pests:

• Slugs
• Snails
• Vine Weevil

Diseases:

• Leaf spot (various fungal pathogens)
• Root rot (in poorly drained soils)

Other:

• Leaf scorch (caused by excessive sun exposure or dry conditions)
• Poor flowering (due to insufficient light or nutrient deficiencies)
• Slow growth (in compacted or nutrient-poor soils)

Rarity & Value

Rarity:

Certain Epimedium varieties are considered rare due to several factors. Some species have limited natural habitats, making them less accessible and more challenging to obtain. The slow growth rate and difficulty in propagation of specific cultivars can also contribute to their scarcity. Additionally, new hybrids with unique characteristics or desirable traits, such as unusual flower colors or variegated foliage, may be highly sought after by collectors, driving up their rarity and value. The introduction of new species and cultivars by specialized nurseries also creates waves of high demand that contribute to scarcity.

Value:

The market value of Epimedium specimens is influenced by several factors. Size and maturity play a significant role, with larger, well-established plants typically commanding higher prices. The quality and stability of variegation, if present, can also significantly impact value, as highly variegated and stable varieties are often more desirable. The origin and provenance of the plant, particularly if it is a rare or newly introduced species, can also influence its value. Furthermore, current collector trends and the overall demand for specific varieties can drive up prices. The presence of unique or unusual characteristics, such as double flowers or exceptionally large leaves, can also add to the plant’s value.