ColoMarilyn - Yes, they can grow in almost 100% full shade. I have quite a few that live in my front yard that get less than 2 hours of sun a day and they do just fine. They're not as big as the ones in full sun, but they're still nothing to sneeze at.. growing 2-2.5' tall and about 2' around. The ones in full sun usually get 2-3ft tall and about 3-4' around. Go for Agastache cana as that's my best one for shade. And I know that one will survive our winters!
