Impatiens (Impatiens walleriana) can grow up to 2 1/2 feet, depending on the variety, and bloom in a variety of colors including red, orange, purple and white, as well as swirled varieties. Unlike many flowers, impatiens grow well in the shade, and prefer it to full sun.
Impatiens like to stay in the shade. Although they can live in full shade, they might not bloom as well as in medium to light shade. Their favorite type of light is filtered -- not direct -- sunlight for four hours or less per day. These flowers work well under trees or in areas where your house or other structures create shade that lasts all day. Suitable for flowerbeds, these plants also thrive in containers.
What Happens in Full Sun
When impatiens area in full sun, all day, they dry out quickly. This keeps the plants from blooming and growing, resulting in stunted plants with leaves that begin to wither and drop off. Western exposure is particularly harmful, subjecting the flowers to the heat of the afternoon sun. Impatiens can survive short bursts of direct sun, but not all-day sun.
Time in the Sun
Not all parts of your yard provide the consistently light shade that impatiens prefer. When you must choose between areas that receive some direct sun during the day, pick spots that catch the morning sun. Try to keep exposure in direct sun to less than six hours per day. If you must plant where they receive afternoon sun, make sure it's no more than two hours of direct exposure. Water impatiens every three to four days to ensure they don't dry out. Plants not in light to medium shade might be smaller and produce fewer flowers than those in their preferred lighting conditions.
Other Important Need
Moderating their sun exposure is only a part of the puzzle of successfully growing impatiens. They need constantly moist soil, so water them at least once a week -- more in hot weather, if the plants receive direct sun several hours per day or if the plants grow in containers. Impatiens need moist but not soggy soil -- too little water causes leaf drop, but too much moisture encourages fungal infection and rot. The soil should form a ball in your hand when you squeeze it, not crumble or run through your fingers in a muddy mess. Impatiens grow as perennials in U.S. Department of Agriculture plant hardiness zones 10 through 11 but you can grow them as annuals elsewhere.