Pugster Amethyst Butterfly BushFull sized flowers on a very dwarf plant, 'Pugster Amethyst' is another winner from Proven Winners! 'Pugster Amethyst' blooms from early summer through frost with amethyst purple flowers, each with a tiny yellow orange eye in the center. While more important to those who garden north of us, the Pugster series offers vastly improved cold hardiness over other types of dwarf butterfly bush.