Epimedium 'Sulphureum'

Epimedium 'Sulphureum': The Groundcover That Means Business

'Sulphureum' sounds like something your chemistry teacher warned you about. In reality it's a vigorous groundcover with bright yellow flowers floating over bronze-red new leaves. THE ONLY EXPERIMENT THAT WON'T SET OFF THE SMOKE ALARM.

Plant Characteristics:

• Botanical Name: Epimedium × versicolor 'Sulphureum'
• Common Name: Barrenwort, Bishop's Hat
• Height: 25–30 cm (10–12 in)
• Spread: 45 cm (18 in) or more, spreading steadily by rhizomes
• Flowers: Bright yellow petals with paler yellow sepals, about 2 cm (3/4 in) across, in loose, airy sprays
• Bloom Time: Spring (April to May)
• Foliage: Semi-evergreen, heart-shaped leaflets that emerge bronze-red, turn green in summer and often redden again in fall
• Features: RHS Award of Garden Merit, vigorous groundcover, early flowers

Where to Plant: This is the one to choose when you need coverage, so plant it under trees, on shady slopes, or along a foundation where nothing else will stay put. Within a few years it forms a dense, weed-suppressing mat.

Companion Plants: Use yellow 'Sulphureum' as a tough carpet in dry or moist shade with a giant hosta behind. Athyrium 'Regal Red' adds silvery fronds with wine-red centres at 45 cm. Astilbe 'Bridal Veil' brings white plumes at 70 cm in July. Hosta Shadowland® Giant 'Empress Wu' rises behind with huge leaves at 91 to 120 cm. Liriope 'Big Blue' edges the front with grass-like leaves and violet spikes at 30 to 45 cm.

Plant Care: Plant in part shade to full shade in humus-rich, well-drained soil. Water well through the first season. Once established, it tolerates dry shade and root competition better than almost any other perennial. In late winter or early spring, cut the old leaves to the ground before the flower stems appear. The flowers show off better and the fresh foliage stays clean. It spreads by underground rhizomes, so it fills in faster than most epimediums. Divide in late summer or early fall to share it or to keep it in its lane.

History: Epimedium × versicolor is a garden hybrid between the Japanese Epimedium grandiflorum and the Caucasian Epimedium pinnatum subsp. colchicum, first raised at the Ghent Botanic Garden in Belgium. 'Sulphureum' is one of the most commonly grown epimediums and holds the Royal Horticultural Society's Award of Garden Merit.

Final Thoughts: Use it to fill the dry, shady slope you've given up on. IT FINISHES THE JOB WHILE YOU FINISH YOUR COFFEE.