What: Helleborus x sternii, commonly called Stern’s hellebore, is the product of two great parents. Corsican hellebore brings somewhat coarse blue-green foliage, green flowers and cold hardiness to the match, while Helleborus lividus (from Majorca) is a cold-tender, compact grower with lovely burgundy stalks and flowers. The resulting combination is a plant that we can grow to Zone 6. It is compact with beautiful, blue-green leaves set off by burgundy stalks. Its flower buds are flushed with deep red and open in late winter to reveal their chartreuse interiors. The flowers of Helleborus x sternii are held on strong stalks and last well, looking good into late spring. This hybrid takes after its Mediterranean parents in its tolerance of full sun. Plants of Helleborus x sternii vary, sometimes resembling one parent more than the other, but all are garden worthy.
Where: This hellebore will grow best in full sun to light or open shade. It prefers a well drained or sandy soil, but will tolerate clay if drainage is adequate.
Size: The hybrid hellebore grow to be 2-feet-6-inches tall and 2 feet wide when mature.
Care: Stern’s hellebore is tough and long-lived if left undisturbed. Once established, it is fully drought tolerant. Use minimal fertilizer to keep plants from flopping as they mature. New growth will appear at the base in late winter. Once the flowers have faded in April, cut the flowering stems to the ground being careful not to damage the new growth.
— Richie Steffen, Great Plant Picks