Understanding what "partial shade' means will greatly improve your success as a shade gardener, says Galveston County master gardener Linda Steber. Partial--or half, dappled, semi or medium--shade means your plants will have four or five hours without direct sun between 10 a.m. and 6 p.m., when the light is strongest. Alternatively, it means you have sun-filtering trees that throughout the day give your plants equal sun and shade. Many flowering plants thrive in partial shade.
Bleeding heart (Dicentra eximia) is a perennial native to Appalachian Mountain forests. Hardy to minus 40 degrees F, it stands up to 18 inches high and wide. This spring and summer bloomer or has greenish gray, fern-like basal leaves. Between April and July, its leafless stems rise above the foliage. They bear pink or red-purple heart-shaped flowers. Protruding interior petals give the appearance of drops of blood at the base of each bloom. In cool climates, bleeding heart will flower well into the summer, according to the Missouri Botanical Garden. Where summers are hot, flowering ceases and possibly resumes when things cool off in the fall. Use this plant in a partially shaded border, rock or woodland garden. It needs consistently moist (not wet), humus-rich well-drained soil.
Azalea (Rhododendorn indicum) is a Japanese native plant reaching 2 to 3 feet high with an equal spread. Semi-evergreen, it's hardy to 0 degrees F. Azalea's 1.5-inch, lance-shaped, glossy green leaves develop a red tinge in the winter. In May and June, it brightens shade gardens with funnel-shaped red flowers. Like all members of the rhododendron family, azalea suffers from a number of pests and diseases. They include mites, scale, borers, root rot and powdery mildew, according to the Missouri Botanical Garden.
Providing your plant with the proper growing conditions should limit its vulnerability to these problems. Give it partial shade and organically rich, acidic (pH below 6.8) well-drained soil. Plants in poor drainage are likely to develop root rot. Mulch the roots to retain moisture. Remove flower clusters as soon as they finish blooming.
Annual blue-eyed Mary (Collinsia verna) brings spring blooms to woods throughout the eastern United States. Reaching up to 2 feet high and 18 inches wide, the wild plant often forms colonies spreading for more than an acre. Its stems have oval lower and lance-shaped upper green leaves. In April and May, blue-eyed Mary has bicolored flowers. Their blue lower and white upper lobes are visible; a fifth lobe remains concealed. The plants set seed and die back by midsummer. Use blue-eyed Mary in annual borders or woodland gardens. Sow seeds for the following year in summer or fall. Plant them in partial shade and rich, well-drained moist loam.