It looks like you'll have a very full bed of hosta under your tree when they mature. That should be beautiful. You mentioned growing clematis on the ground...I thought they didn't like to get their leaves wet. Do they do well for you on the ground?
I've been adding heuchera and shrubs to my beds. I'm surprised how many blooms I get on my hibiscus that are in the Shade. Here's a picture of one part of a bed that has some hibiscus, but no blooms yet.
