Penstemons generally have tubular flowers that flare out at the end. They are undemanding and the foliage looks nice from the beginning of the growing season to the end. Many penstemons are not hardy in our Zone 4 garden. Fortunately we have found some that are and will continue to try others.
PEME P. Mesa - Deep lavender blue spikes 6 weeks starting in June on 20" stalks. May rebloom in cool climates. Spring or fall.