I have P. 'Rote Glocke' in part-shade (morning and some midday sun, then shade) and another in full sun. Both do well, although the one in full sun tends to melt down mid summer and just disappear. The one in part-shade was newly planted last year and I forget if it also went dormant mid-summer or not. I'll keep an eye on it this year. Both are at the seedhead stage now, which I like almost as much as the flowers.
