Clay soil can cause a lot of problems, so you need to pick your plants carefully. Clay soil is heavy, drains slowly, has a high alkaline content and warms up slowly. Flowers planted in clay soil need to be able to handle wet soil. Clay soil is a combination of silt, minerals, organic matter, air, water and clay, with 50 percent of the soil containing clay particles.
Stella de Oro Daylily
The Stella de Oro is a dwarf form of the daylily, reaching about 12 inches in height. It grows well in zones 3 to 9, all but the coldest and hottest of the hardiness zones in the continental United States. The leaves are a dense green that form a clump. The flowers are trumpet-shaped, fragrant and golden-yellow in color. The Stella de Oro can be used in mass plantings, as a border or in containers. Stella de Oro can grow in normal, sandy or clay soil. It blooms from early summer to mid fall and is easy to care for.
Bee Balm flowers attract butterflies, hummingbirds and bees. The flowers come in pink, red, purple or white and in single and double forms that grow in large heads made up of 20 to 50 flowers. The leaves grow directly opposite each other and have toothed edges. The leaves and stems are covered in very fine hairs. Bee Balm will bloom throughout the summer and grows 2 to 4 feet in height. Bee Balm does well in wet clay soil, is easy to care for and prefers full sun to light shade. Bee Balm is susceptible to mildew, so the more sun, the better. It is a perennial that is hardy in zones 3 to 9.
Coreopsis is hardy in zones 3 to 8 and produces a bright yellow flower that resembles a daisy. It will bloom throughout the summer and into the fall. The leaves are mostly green that can be cut or fern-like and form a clump under the flowers. They have a bushy appearance. Some varieties are compact, while others spread. The only soil that coreopsis does not do well in is soil that is very waterlogged. Full sun will produce the most flowers. The plant needs very little fertilizer.