I have several, most of which get mid-day sun as well as a couple that are in deeper shade. They are all about the same height at this point and full of flowers starting to bloom.

Did you have a lot of dead wood on the ones in the sun after the winter? How old are the plants?

I have about six of them planted in a crook of the house that shelters them on the south and the west sides. There is a very large maple nearby, but for a couple of hours a day, about half the shrubs get direct sun. In hot weather, these wilt a bit during the day, but they are also nearly twice as large as the ones that get less sun - and they flower better. I guess it's a trade-off!