PHYTEUMA nigrum. Central Europe. The phyteumas are known among rock gardeners as exceptionally choice, but often difficult, members of the bellflower family. This is clearly one of the easy ones, even self-seeding here and there. It makes dense, low tufts with narrowly heart shaped leaves. Branched 6-8" stems issue from the clumps in late spring and summer, carrying many 1" heads of tiny purple blossoms. Cutting off the spent flowering stems encourages further waves of bloom. Sun or light shade, well drained soil, moderate watering. Probably hardy to 0^oF.