Clay Busting Plants and Techniques 

Clay is common here.  Rock hard clay can be broken up and amended with organic matter like peat moss, thick leaf mold, soil conditioners (coarse organic materials); and bark compost to a limited extent.  DO NOT USE SAND.  Mulch only from above.  Gypsum is not recommended in the East. You can also improve your soil by planting clay "busting" plants. Over time, your soil will improve just by planting these.

Perennials:

Amsonia (Bluestar)

Asclepias (Milkweeds)

Coreopsis (Tickseed)

Echinacea (Coneflower)

Iris germanica (Bearded Iris)

Rattlesnake Master (Eryngium yuccifolium)

Rudbeckia (Black Eyed Susan)

Helianthus x laetiflorus and others (Perennial sunflowers)

Heliopsis helianthoides  (Ox Eye Sunflower)

Hemerocallis (Daylilies)

Heuchera (Coral Bells)

Hostas

Liatris spicata (Gayfeather)

Monarda (Bee balms)

Panicum virgatum  (Switch Grass)

Parthenium integrifolium (Wild Quinine)

Ratibida pinnata and columnifera (Gray headed coneflower; Mexican hat)

Silphium family (Cup plant, Rosin Weed)

Solidago family (Goldenrod)

Sorghastrum nutans (Indian Grass)

Symphyotrichum novae-angliae (New England Asters)

Vernonia (Ironweed)

Shrubs

Berberis (Barberry) - limit to sterile forms like Orange Rocket 

Buddleia (Butterfly Bush) - look for sterile forms

Cornus (Dogwood)

Cotoneaster 

Forsythia

Hydrangea

Mahonia - limit to sterile, non-invasive forms like 'Soft Caress''

Pyracantha

Viburnums

Weigela