dwarf alberta spruce, purple leaf plums, smoketree...what else?
I have begun planting a slight slope in my backyard. Along the back row are three Dwarf Alberta Spruce (spaced about 10ft apart). I also have two purple leaf plums and one smoketree yet to plant (am planning on making the smoketree the centerpiece). I would like to plant 2-4 other bushes or perennials...but I'm not sure what. I'm considering something that gets to maybe 3-5 feet tall and wide (but that's negotiable). I would prefer something with green leaves since the others all have darker leaves...but I need to find something that "works well." I would also like something that flowers...maybe late spring or early summer. I should mention that I will make the slope look somewhat rocky...not sure if I'll do random rocks or build a couple of terraces (again, it's not terribly steep, but a terrace or two would work).
Any ideas what might be suitable? Or even if it doesn't fit my preferences, I'm open to new thoughts. I still plan to have room to tuck in a few smaller annuals and perennials...but I might wait until next year to fill in the gaps. I was looking at a Weigela today, but not sure if that would work or not.
Let me know...I'm willing and ready! Thanks.