Pugster® Amethyst ('SMNBDL') Butterfly Bush is a more cold tolerant compact Buddleia, with large lavender purple blooms on short sturdy stems. Pugster® Amethyst starts blooming in June and keeps on flowering until early fall. A Spring Meadows introduction, this Buddleia is recommended for use in rock gardens, perennial beds and tighter sites than most Buddleia can handle.