Hi all!
Yes JB, the flowers on some streps can get very heavy and many varieties do not have strong enough peduncles (stems) to hold them up. This is something that the Ukrainian and Polish hybridizers continue to work on. I rarely ever stake mine, but I have many that the blooms fall over. Like Greg said, if it has a lot of blooms, with some falling and new ones coming in, it can look OK.
All of your plants look very pretty! I love the blooms on Sashenka!
Karen