Tried and true shade-loving plants like hostas, impatiens and coleus certainly deserve a prominent place in the summer shade garden. Many other summer bloomers, however, are equally at home in partial to full shade. Some of them peak during a single summer month, while others provide color from early summer to the first days of fall. Don't overlook them as possibilities for brightening your garden's sun-deprived spots.
Yellow archangel (Lamium galeobdolon), a mint family perennial native to western Asia and Europe, is hardy to minus 30 degrees F. A low-growing--up to 12 inches high--June bloomer, it spreads between 1 and 2 feet. Shade-loving yellow archangel has oval, silver-blotched green leaves. In June, its 3/4-inch, lobed yellow flowers bloom in clusters on stems rising above the foliage.
The plant spreads by its creeping stems and may become invasive, cautions the Missouri Botanical Garden. Use yellow archangel as a ground cover in partial--for best results--to full shade. It prefers averagely moist, well-drained locations but withstands short dry periods once established. Prune back leggy plants to encourage heavier foliage.
Hardy begonia is a popular, summer-blooming shade plant native to China, Japan and Malaysia. Tolerant of temperatures to minus 10 degrees F, it's an annual in areas with colder winters. Standing up to 2 feet high and wide, it blooms from July until first frost. This tuberous plant forms a bushy foliage clump with 4-inch, oval leaves. They have green surfaces and red-veined, greenish-red undersides. Plants produce clusters of 1-inch, female and male pink blooms. Hardy begonia self-sows.
Use hardy begonia, recommends the Missouri Botanical Garden, in mixed shade borders with hostas or ferns. It likes partial to full shade and consistently moist, well-drained rich soil. Provide winter mulch in areas where it's marginally hardy. Removing spent flower heads (deadheading) will prolong the bloom.
Bugbane (Actaea dahurica) is a large--to 6 feet tall--buttercup family perennial hardy to minus 40 degrees F. It has an upright habit and branching stems with fernlike, dark-green leaves. Foliage forms 3- to 4-foot clumps. One- to 2-foot stems with fluffy cylindrical spikes of white flowers appear in August and September. The blooms' mild fragrance acts as an insect repellent. Flower spikes may need staking if they bend toward sunlight.
Susceptible to leaf spot and rust, bugbane is otherwise largely pest- and disease-resistant. Use it, suggests the Missouri Botanical Garden, for summer color against a darker background in shade gardens and borders. It's most impressive planted in groups. Provide averagely but consistently moist, fertile soil and partial to full shade. Plants in dry soil may develop leaf scorch. Protect it from strong winds.