Along with coleus and caladium, impatiens are a sure-fire flowering plant for shady garden locations; however, they can be grown in sunny gardens if certain factors are considered. The stems of impatiens are waxy and succulent with lots of moisture. If too much sunlight heats up the leaves and soil around impatiens, wilting occurs quickly, especially if the soil is dry. If frosts never occur, impatiens continue to grow indefinitely, persisting as an herbaceous perennial.
Garden centers across the U.S. grow and sell two types of impatiens. The common type of impatiens (Impatiens walleriana) grow as a branching mound 24 inches tall and equally wide. The leaves are light green and thin but oval in shape. These impatiens quickly scald or dry up if exposed to direct sun rays from spring through fall. The hybrid New Guinea impatiens, however, tolerate significantly more direct sun -- even in summer -- without much detriment. These types are thicker stemmed with larger, darker green leaves and mature up to 18 inches tall and wide.
Plant common impatiens where they receive bright, indirect light in partial to full shade locations. They should receive no more than four hours of direct sun rays, mainly when the sun angle is low either in the morning or evening. New Guinea impatiens flower better in brighter light conditions. Plant them where they receive partial sun to partial shade, between four and eight hours of direct sun daily.
Sunlight intensity and heat is greater in the more southern latitudes of the U.S. While impatiens may prosper in nearly full sun conditions in the cool summer areas near Seattle, Minneapolis or Boston, they will quickly wilt and dry up in full sun farther south or at higher elevations with arid air. In Hawaii, Puerto Rico and South Florida, all impatiens may be grown in partial to full sun during the frost-free winters months of November through February. In the southern U.S., always plant impatiens with considerable shade, especially from 9 a.m. to 6 p.m. during summer.
The Need for Moisture
Gardeners can offset some of the damaging effects of too much direct sunlight on impatiens by monitoring soil moisture. Plants with a constantly moist soil, but not soggy wet, will not wilt or scald as quickly as those growing in drier soils. Mulching soil helps shade the ground and keeps the soil cooler and moister longer. Amend garden soils with lots of organic matter such as manure or compost to improve fertility and the moisture retention of all soil types, especially sand.
- "A-Z Encyclopedia of Garden Plants"; Christopher Brickell and H. Marc Cathey, eds.; 2004
- Photo Credit Photos.com/Photos.com/Getty Images
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