By Julie Martens Forney
Native soils in the Mid-Atlantic run the gamut from sandy to acid to loamy blends. Clay soil is perhaps the most difficult type gardeners face. This heavy soil drains slowly and dries to a concrete-like finish. Clay soils are slow to warm in spring, and difficult to dig.
But gardening in clay isn’t hopeless. Discover perennials that survive in clay, including black-eyed Susan (Rudbeckia fulgida), above, and learn some easy tips for gardening in clay soil.
PERENNIALS FOR CLAY SOIL
The secret to season-long color in clay soil is choosing plants that don’t mind the extra moisture.
Start with spring bulbs. Most bulbs need well-drained soil to thrive. A few, including daffodils (Narcissus ‘Golden Echo’), grape hyacinth (Muscari), and crocus, survive in clay soil.
Segue into summer bloomers. Count on long-season bloomers, such as black-eyed Susan, catmint (Nepeta) and bee balm (Monarda didyma), to carry the summer garden. Use meadow rue (Thalictrum aquilegiifolium), shown, astilbe, and Siberian iris (Iris sibirica) for accent color with flowers that appear for shorter times.
Plan for fall color. Asters, shown, offer bright blooms in autumn. Also try toad lily (Tricyrtis), obedient plant (Physostegia virginiana), and ox eye daisy (Heliopsis) for fall flowers.
TIPS FOR GARDENING IN CLAY SOIL
Improve clay soil by adding organic matter to loosen it and create air pockets for roots and microorganisms. Try these tricks to work organic matter into clay soil:
- Dig and replace. In a spot with heavy clay, dig out the clay soil, toss it on a tarp, and blend it with compost and bagged potting soil, then return it to the bed. Store extra improved soil in a loosely closed plastic bag.
- Always improve soil. Every time you plant, dig the hole twice as large and add organic matter such as compost, or the extra soil you saved from the first tip.
- Add mulch. Sun plus clay equals bricks. Avoid the brick effect by covering clay soil with 2 in of mulch. Use shredded bark—it adds organic matter as it decomposes.