Good tips on planting an "attractive and functional" garden in Slate. I quibble a bit with the bit about putting a circle of plants under a tree.

Well, I don't quibble that it shouldn't be a circle -- if you are going to plant around a tree the swath of bed should be large-ish and probably curving instead of a tiny little circle around a big, stately tree. Smaller trees like dogwoods work their way better into a flower bed than do things like maples and oaks, too. And if you are planting under a tree, you do have to choose something that can take a drought when the tree soaks up all the water first or shields the ground with its leaves. Even so, I think trees can be surrounded by plants close to their base in an attractive manner.