The plant commonly known as Goat Weed, or Horny Goat Weed, belongs to the genus Epimedium. This perennial herb, also nicknamed “Bishop’s Hat” or “Fairy Wings,” is recognized for its distinctive foliage and delicate spring flowers. Visual identification requires examining its overall growth pattern, the anatomy of its leaves, the structure of its blooms, and variations across its many species.
Overall Structure and Growth Habit
Epimedium plants are low-growing, herbaceous perennials that typically function as ground cover. Most species reach a modest height, generally ranging from 8 to 16 inches, forming dense, slowly spreading clumps. The root system consists of woody or creeping rhizomes, which help the plant form a tight mat.
Leaves and flower stalks emerge directly from these rhizomes, giving the plant a tufted appearance. Stems are thin and wiry, often with a reddish tint, lending a delicate, airy quality to the structure.
Detailed Anatomy of the Leaves
The foliage of Epimedium is the primary means of year-round identification. Leaves are compound, with a single stalk holding multiple leaflets, typically arranged in groups of three. Individual leaflets are commonly heart-shaped (cordate), ovate, or distinctly arrowhead-shaped (sagittate), depending on the species.
The texture ranges from leathery to finely textured, and edges are often finely serrated. A unique characteristic is the dramatic seasonal color change. New growth emerges in rich tones of bronze, copper, or deep red before maturing to green for the summer. Semi-evergreen varieties re-color in autumn or winter, adopting striking shades of maroon or reddish-purple.
Characteristics of the Blooms and Fruit
The flowers of Epimedium are borne on thin, branched stalks that typically rise above the foliage, creating an airy effect. The bloom structure is complex and distinctive, leading to the nickname “Bishop’s Hat” due to its intricate shape. Each flower possesses four outer sepals and four inner petals, which often feature prominent, backward-pointing spurs.
These spurs range from short to long and curved, sometimes giving the flower a spider-like appearance. Flower colors are diverse, encompassing white, yellow, pink, purple, and orange, and are often bicolored. Following the spring bloom, the plant produces small, dry seed capsules known as follicles.
Visual Differences Between Common Varieties
The Epimedium genus includes numerous species and hybrids, each with subtle visual distinctions. Common species include Epimedium grandiflorum, E. sagittatum, and E. brevicornu. E. grandiflorum is notable for its large, showy flowers with exceptionally long spurs, often appearing orchid-like.
In contrast, E. sagittatum is recognized by its leathery, pronounced arrowhead-shaped leaves and short-spurred flowers. E. brevicornu typically features thin, larger leaflets and smaller, starry flowers. Varieties are also categorized by life cycle: some are deciduous, losing all leaves in winter, while others are evergreen or semi-evergreen, retaining dark, rich-colored foliage during cold months.