Chinese Foxglove was a pleasant surprise in my garden. It was slow growing the first year, and I didn't expect it to survive our zone 5 winter. But the following spring it came back strong and bloomed all summer long.
Rehmannia 'Popstar' has raspberry-pink flowers with spotted throats. It spreads by underground runners, which makes it a nice groundcover. Also known as Rehmannia elata. Hardy in zones 7-11.
Sowing Rehmannia angulata Seeds:
Sow indoors 8 weeks before the last frost date. Sow on the surface. Full sun to part shade.