I'm not sure if I can help you since I mostly grow annuals but I have some questions that might help people give you better suggestions. How tall do you want the taller plants to get? Do you want the shorter plants to be a lot shorter than them or say half the height? Do you start your own seeds? Or would you need to order plants online or go to a nursery? If so, if cost an issue? Are you interested in biennials if they bloom the first year and/or reseed? How unusual do you want the plants to be? Something no one would recognize or maybe something people know but in a different form or unusual color? Answers to questions like these might make it easier for people to steer you to the right plants for your yard. I envy your blank slate!
