Flowers
Common Name: bishop's hat
Type: Herbaceous perennial
Family: Berberidaceae
Native Range: Armenia, Azerbaijan, Iran, Turkey
Zone: 5 to 8
Height: 0.75 to 1.50 feet
Spread: 0.75 to 1.50 feet
Bloom Time: March to May
Bloom Description: Yellow
Sun: Part shade to full shade
Water: Dry to medium
Maintenance: Low
Suggested Use: Ground Cover, Naturalize
Flower: Showy
Tolerate: Rabbit, Deer, Drought, Heavy Shade, Erosion, Dry Soil, Shallow-Rocky Soil
Culture
Easily grown in average, dry to medium, well-drained soils in part shade to full shade. Prefers loose, organically rich loams with even moisture in part shade. Tolerates drought once established. Dense clumps slowly spread by rhizomes. Evergreen foliage in mild winter climates. In St. Louis, cut back old foliage in late winter.
Noteworthy Characteristics
Epimedium pinnatum is a rhizomatous, clump-forming, evergreen perennial that grows to 8-12" tall. It is native to woodland areas of the Caucasus (subsp. pinnatum from regions near the Caspian Sea and subsp. colchicum from regions near the Black Sea). Showy flowers (to 3/4" wide) feature bright yellow petal-like inner sepals, red spurs, and minute brownish petals. Flowers bloom in spring (April-May) in terminal racemes (12-30 flowers) atop leafless flowering stems (plant leaves are all basal) rising to 12" tall. Basal leaves are biternate (9 leaflets) or pinnate (5 or 11 leaflets). Dark green leaflets (to 3" long) with red or white surface hair (maturing to hairless) have acute tips, cornate bases and serrate margins.
Subsp. colchicum grows slightly taller (to 16”), spreads more slowly, has larger flowers and often produces toothless leaflets. It is noted for dense, spreading mounds of compound foliage with ovate, sparsely toothed to entire leaflets (2-5” long) and for a spring bloom of outward-facing, bright yellow flowers with yellow or brown spurs. E. pinnatum subsp. colchicum is synonymous with E. pinnatum subsp. elegans.
Genus name is of unclear origin and meaning but the Greeks used epimedion for a very different plant.
Specific epithet comes from the Latin word pinnatus meaning feathered in probable reference to leaf shape.
Epimediums are commonly called bishop’s hat (four-spurred flowers of some species resemble a clergyman's biretta) or barrenwort (root extract was once believed to prevent female conception).
Problems
No serious insect or disease problems.
Uses
Ground cover or edger for shady areas. Mass in woodland gardens, wild gardens or naturalized areas. Also effective in partially shaded areas of rock gardens and border fronts. Grows well under trees. Edger for paths and walkways.