Some of the most popular annuals on the market, impatiens are available in several species, most of which prefer cool temperatures, ranging from 60 to 78 degrees F, according to Mr. Impatiens. Though impatiens thrive in temperate climates with cool summers, they can also flourish in warmer areas with diligent watering and shade or in colder climates with full sun and protection from frost. Impatiens, perennials in temperate climates, have a long spring-to-fall blooming season.
In the more temperate areas of the USDA middle zones, such as Zones 7or 8--where minimum temperatures only occasionally fall below freezing and summers are cool--impatiens thrive in full to partial sun with regular watering. In these regions, impatiens are perennial. When temperatures dip below freezing, protect the plants with a cover, or, if potted, bring them inside.
In warmer regions, including Zone 9 and higher (temperatures rarely reach freezing and summers are warm), impatiens can thrive, but only with ample watering. Impatiens should be planted in partial sun to partial shade, with particular attention paid to the moistness of the soil. Plants will wilt in the heat of an afternoon summer in hot areas like Central Florida, but daily watering can keep the plant healthy.
In colder areas, including Zone 6 and lower, impatiens are generally used as annuals and planted for garden color in the spring. When used as annuals in midwest or northern states, from Kansas to New Hampshire, impatiens should be planted after last frost in partial to full sun and soil should be kept moist. Plants will die off at first freeze.