Three kinds of impatiens are commonly grown as annuals in the United States. Impatiens walleriana, also known as busy Lizzy, is a low-growing plant with flat, brightly colored blooms that thrives in shade. New Guinea impatiens (Impatiens hawkeri) is noted for its patterned foliage, sun tolerance and bushy growth. Garden balsam (Impatiens balsamina), also called rose balsam, is a tall, narrow type that resembles a small hollyhock and can take full sun.
A summer annual in all but U.S. Department of Agriculture plant hardiness zones 10 and 11, where it will overwinter, busy Lizzy is the most popular annual in the United States. Plants that bring hot-colored blooms to the shade are hard to find, and this bedding impatiens blooms in orange, peach, pink, magenta, lavender, red, white and bicolors. It takes everything from two to four hours of morning sun to dappled shade to deep shade.
Garden balsam is a tall impatiens that produces single or double cup-shaped flowers along its upright stem. It reaches 1 to 3 feet tall and blooms in pink, purple, red, white or bicolors. Although it will grow in full sun, it prefers protection from hot afternoon sun. It also grows in shade. Garden balsam is an annual in all USDA zones, but it will multiply by seed in warmer zones, 9 through 11.
New Guinea Impatiens
New Guinea impatiens plants have large, narrow leaves with yellow, orange, red and purple markings that rival its flower colors. They grow 1 to 2 feet tall in shade or sun and bloom in lavender, magenta, red, pink, orange and white. If planted in the winter in USDA zones 10 and 11, New Guinea impatiens thrives in sun. Otherwise, it needs protection from hot afternoon sun. It will also grow in shade.
While the most popular forms of impatiens are grown as annuals, types that overwinter in USDA zones as cold as 5 are unusual in gardens. They all thrive in shade. Impatiens stenantha, hardy in USDA zones 7 through 10, is an upright plant with yellow blooms with red-speckled throats. Impatiens omeiana is a creeping perennial hardy to USDA zones 6 through 9 with patterned leaves in silver, green and red. Impatiens omeiana “Sichuan Gold” is cold hardy to USDA zone 5b.