Clay soil has densely packed particles that make it thick and hard to drain. Standing water can be fatal to plants not acclimated to it, causing a fungal disease called "root rot." Plants that grow in wet areas in their natural habitat grow well in heavy, wet clay soil. The soil can also be made more habitable by adding organic matter.
Common sneezeweed (Helenium autumnale) is also known as fall sneezeweed and is a member of the aster family. The plant got its name because it was originally used to make snuff, a powdery substance that was inhaled to make the person sneeze for the purpose of ridding the body of evil spirits. The plant is a perennial that grows from 2 to 5 feet tall and produces green, elongated leaves and daisy-like flowers with a raised, green-yellow center surrounded by yellow, drooping petals that bloom in July, August and September. Plant common sneezeweed in full sun and a damp soil. The plant is found in all areas of the continental United States and Southern Canada in moist, open-areas near bodies of water. Butterflies are attracted to the plant's nectar.
Chameleon houttuynia (Houttuynia cordata 'Chameleon') is a member of the lizard's-tail family. The plant is a groundcover that grows up to 1 foot tall. Chameleon produces oval-shaped, green leaves that grow up to 3 inches long with red, bronze, cream or yellow around the edges. The white flowers bloom in June and July and are mostly hidden under the leaves. Plant chameleon houttuynia in full sun to partial shade and in a soil that is moist to wet. The plant is hardy in USDA zones 5 to 8.
Dense Blazing Star
Dense blazing star (Liatris spicata (L.) Willd), also known as dense gayfeather and marsh blazing star, is a member of the aster family. The plant is a perennial that grows from 3 to 4 feet tall and produces grass-like leaves and rose-purple flowers that grow in clusters on long spikes in July, August and September. Dense blazing star is found in the eastern half of the country, from Southern New England to the Gulf Coast and as far west as Michigan, Missouri and Louisiana. Plant it in full sun and a soil that is moist to wet. Butterflies, song birds and hummingbirds feed on the plant.