Common Name: bishop's hat
Type: Herbaceous perennial
Family: Berberidaceae
Zone: 5 to 8
Height: 0.75 to 1.50 feet
Spread: 0.75 to 1.50 feet
Bloom Time: April to May
Bloom Description: Purple
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, acidic, dry to medium moisture, well-drained soils in part shade to full shade. Prefers loose, organically rich loams with consistent moisture in part shade (sun-dappled or morning sun). Foliage will usually burn in full afternoon sun. Tolerates full shade. Also tolerates drought and dry shade (rhizomes hold moisture) once established. Intolerant of alkaline soils. Clumps spread somewhat slowly but will form attractive colonies over time. E. grandiflorum is deciduous in USDA Zones 5-6. Although sometimes semi-evergreen south of Zone 6, foliage still tends to disappear on its own by spring. Any foliage that does survive winter should be cut back in late winter prior to emergence of new growth. Propagate by division in early spring or fall.
Noteworthy Characteristics
Epimedium grandiflorum is a dense, rhizomatous, clump-forming, usually deciduous perennial that typically grows 10-15” tall with a spread to 18-20". It is native to deciduous woodland areas of Japan, Korea and Manchuria. Spidery flowers (1-2" across) with pale rose to violet inner sepals and white petals with long reflexed spurs (each to 1") bloom in tight racemes (to 4-16 flowers per raceme) above the foliage in spring (April-May) atop flowering stems bearing one biternate or triternate leaf. Each flower has eight petal-like sepals and four petals (to 3/4" long) with long spurs (suggestive of columbine) which usually exceed the length of the inner sepals. Variants and cultivars come in a wide variety of different flower colors. Compound, medium green leaves form attractive foliage mounds. Leaves are both basal and cauline and either biternate or triternate. Narrow ovate to broad ovate leaflets (to 2-4” long) have spiny-toothed margins, cordate bases and acuminate to acute tips. New leaves emerge in spring with a beige to bronze cast but quickly mature to medium green.
Synonymous with and formerly called Epimedium macranthum.
Genus name is of unclear origin and meaning but the Greeks used epimedion for a very different plant.
Specific epithet from Latin means large-flowered.
Epimediums are commonly called bishop’s hat (four-spurred flowers of some species members resemble a clergyman's biretta) or barrenwort (root extract was once believed to prevent female conception).
‘Pierre’s Purple’ produces large-spurred, wine purple flowers in spring well above the emerging foliage. Compound, medium green leaves with spiny-toothed oval leaflets (to 3” long) on wiry stems form attractive foliage mounds. New leaves have a bronze cast in spring.
Problems
No serious insect or disease problems. Mosaic virus (transmitted by aphids) is the main disease problem.
Uses
Ground cover or edger for shady areas with tolerance for dry shade once established. 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.