It can be difficult to find plants that tolerate both shade and minimal moisture. The area beneath mature trees is particularly difficult. Tree roots take in a great deal of the water, and the canopy blocks rain from reaching the soil underneath. Buildings can also cast shade, and roof overhangs block rain from reaching foundation plantings. By choosing the right perennials you can turn dry shade into carefree gardening.
One of the best dry-shade plants is the lenten rose (Helleborus orientalis). The winter flowers are in clusters of single or double five-petaled flowers. The blooms may be white, ivory, pink, red, yellow and purple. 'Winter Dreams Black,' has deep purple nearly black flowers. 'Ivory Prince,' has creamy flowers with rose-colored edges. Hellebores cross-pollinate so if you have several varieties, the seedlings will vary in color.
The evergreen foliage adds color to the perennial garden year round. Give them shade and humus-rich soil and they will perform for many years. Hellebore orientalis is hardy to U.S. Department of Agriculture's Plant Hardiness Zone 6. There are other hellebore species that are more cold hardy. The white Christmas rose (Helleborus niger) is hardy to USDA zone 3.
Few foliage plants rival hostas for the shade garden. They may reach larger proportions given water, but do fine in dry conditions. They are sometimes called plantain lilies, and are a member of the lily family. There are endless combinations of foliage colors. Many have variegated stripes or edges. The width of the leaves can be from 1 to 8 inches depending on the plant, but all are a basal clump of strap-like leaves. Hosta's are rhizomatous plants, when they die back in the fall they can be divided and transplanted.
They foliage comes in shades of green, blue, white and yellow. The small bell-shaped flowers are arranged on long stems and will be either white or purple. Newer varieties like 'Venus' have large white fragrant flowers. The average hosta will reach from 1 to 3 feet in height, but there are also tiny groundcover hostas like 'Mouse Ear' that are only a few inches tall. Hostas are hardy in all regions.
Coral bells (Heuchera) provide some of the best foliage colors. They can be grown in all garden situations, but are valuable for dry shade. Coral bells can stand alone, act as companion plants, or be massed as a ground-cover. Because they are semi-evergreen they will compliment the garden in spring, summer and fall. They may go dormant in winter but will bounce back in early spring. They are one of the first plants to wake up, and will bloom with the violets and the primrose.
The foliage is nearly round and sometimes ruffled. The most popular coral bells are those with red to purple foliage. 'Amethyst Myst' has purple leaves with silver veins. A green-leaved variety, 'Blood Red,' has vibrant red flowers. There are some with unusual foliage colors, for instance 'Lime Rickey' has chartreuse leaves and 'Amber Waves' has peach foliage. Coral bells can have white, pink or red flower clusters. The blooms are held 1 to 2 feet above the low-growing foliage. Heuchera's are hardy to all regions.
Bishops hat or barrenwort (Epimedium) are delicate woodland plants. The small plants spread by rhizomes, eventually creating a dense ground-cover. The multicolor, heart-shaped leaves add much-needed color to the shade garden. The leaf colors intensify in the fall. Epimediums develop spurred flowers in white, yellow, pink and red colors in the spring. The hardiness zone varies with each species. There are several varieties of Epimedium grandiflorum that are hardy to USDA zone 4. Others are hybrids of Epimedium perralchicum and are hardy to USDA zone 6. An easy one to grow is Epimedium versicolor which is hardy to USDA zone 5.