'Obsidian' is a compact, darkly dramatic mound-forming perennial, spreading to 40cm, with distinctive lobed, glossy leaves, reddish-black in spring, darkening to near-black as they mature. Racemes of small creamy flowers are borne above the leaves in summer on dark reddish stems, usually 25-40cm, sometimes taller. Will grow equally well in sun or partial shade on any reasonable garden soil.