Easy to overlook for half the gardening year, Helleborus argutifolius, the Corsican hellebore, is coming into its own right now. From mounds of jade green serrated leaves, flowers of the lightest apple green are emerging, luminous against their dark backdrop. They make an ideal partnership with primroses, pulmonarias and narcissi in full sun or very light shade. Despite its Mediterranean origins, H. argutifolius is as tough as old boots, seeding everywhere. Young plants are easy enough to pull out or transplant as needed. The flowers will last for many months, into the early summer when smart new leaves will have replaced the old.