Substitute for Dragon Wing Begonias
For the past several years I've been planting Dragon Wing Begonias in the rail boxes on my deck, and they've been BEAUTIFUL. But the problem -- if you can call this a problem -- is that they've done TOO well. They've grown so tall and so full that their weight causes the boxes to topple off the railing. It's my understanding that these plants really can't be pruned to maintain a smaller size.
So my question is, is there something else that's colorful that will do well in a part sun location in zone 6b that I should consider planting in place of the begonias? Thanks!