I re-imagine my garden all the time. I've been here for more than 20 years, so I have to watch myself because of lack of space for planting new things. The moving about of plants is part of the fun... or the chore of having a garden. This winter we had an unusually long snow season and several of my plants were damaged. I have senna plants that flush out into beautiful yellow blooms in August and they really suffered. Some of them were just too damaged to keep. I'd been eyeing the bed they live in for a while and the winter damage gave me the push I needed to re-do. I'm sure that senna plants can be weaved together to form a green wall. I've decided to try and grow a blooming bower. They aren't quite big enough yet, just little stick looking things really. Still, a half-day of work and it looks 100% better.

Back to your frustration... I think you may be reading it wrong. It seems more like you're creatively visualizing your garden. You're probably better off leaving without anything if you have a sense that before you buy you need to move things about.