Zephirine, thank you for your reply, but the flowers of my Scutellaria are more pale.
The only additional info I have is that only one plant out of 5 survived in my zone 6. Will have to wait if that one returns this year, because we had a few spring days and suddenly the temps went down to -15°C , hardly without a snow cover.
I also got a suggestion it should be S. latiliflora, but also that one is not as pale as mine.
Well, I got seeds of S. latiliflora and winter sowed them, so maybe I can compare it this year.
Anyway, all suggestions are welcome.