shrubs / small trees that tolerate clay
We moved into this 3 year old house with a flower bed on our front lawn (north east exposure) last year. It's our second summer in this house and the little mountain ash in the flower bed still has no leaves on it; but the inside of the branch is still green. It turns out that it's all clay below the 4-5 inches of soil in the flower bed.
So my questions are:
1) what do I do with the mountain ash? Is it dead?
2) if we were to plant something else in its place, what would survive the clay soil in Zone 3?
3) someone has suggested that the clay would be too big a problem and we should think about just putting rocks in the bed. We do have 3 spireas and a rhododendron spread out in the same flower bed (they look a bit "anemic" as well).
Thanks in advance for all your suggestions to us newbies.