It's curious to me why I don't see this stunning perennial in more gardens. 'Snowtop' has masses of large, exotic, pure white, trumpet-shaped flowers in late spring. The lush foliage looks somewhat like Acanthus (Bear's Breeches). It will rebloom if cut back after flowering. Give this unique perennial a try.
Asia - China and Japan
Grassy places and scrub around 2000m. Pastures and open grassland, 2400-3500 m., but it is now uncommon in its native range.