I live in zone 5b of Pennsylvania. I also have clay soil. I find that plants termed "invasive" in other areas do well for me here. I suggest old fashioned daylilies, hosta, lamium (dead nettle), azaleas and rhododendrons, purple (or other colored) coneflowers, phlox, creeping phlox, liatris, fairy roses, iris, mints, primroses, narcissus, crocus, goldenrod, and others you can find by websearch like Google.
Best of luck.
By
04/17/2009
I agree with 587 and add hostas of all kinds to that.
By
04/13/2009
Tomatoes do very good in clay soil. Wish I had some here in AL, good luck.
By
04/13/2009
Roses. They love a heavy soil like clay. It holds the water in, roses are heavy drinkers.