Divide the roots very carefully every few years. Echinacea purpurea, the purple coneflower , ranks among the easiest of the summer daisies and prospers in warm, sunny areas. Hepatica americana, round-lobed hepatica , will prosper in the shade of trees or a shady rock garden. The flowers are less significant than the attractive foliage. New foliage appears right after the flowers bloom and lasts through the winter.
Lobelia cardinalis, the cardinal flower , bears tall spikes of red flowers in late summer.
Lobelia isn't too difficult to grow from seeds sown in early spring. Mertensia virginica, the Virginia bluebell , produces stalks of dangling flowers that start out as pink buds and turn into blue, bell-shaped flowers. The foliage is gone by July, so give this plant a neighbor that will sprawl and conceal the blank space. Part shade is best. Thalictrum dioicum, meadow rue , is a graceful perennial that bears flowers in mid- to late spring.