Impatiens, with their vibrant colors and ability to brighten shady spots, are among the most popular bedding plants. A common point of confusion for gardeners is whether they are perennials that return each spring or annuals that must be replanted. The answer depends entirely on geography and climate. Understanding the botanical classification and its relationship to cold tolerance is the key to settling this debate.
Understanding Annuals and Perennials
The distinction between annuals and perennials centers on the length of a plant’s life cycle. An annual completes its entire life cycle—germinating from seed, growing, flowering, producing seed, and dying—all within a single growing season. This is a one-year process that must be repeated annually.
A perennial, by contrast, lives for more than two years, typically returning season after season from the same root structure. Hardy perennials can survive cold winter temperatures, often dying back to the ground before regrowing in the spring.
The True Nature of Impatiens
Impatiens are botanically classified as tender perennials or tropical perennials, not true annuals. In their native tropical and subtropical regions, species like Impatiens walleriana grow year-round, behaving as a perennial shrub. They do not possess the genetic hardiness to withstand frost, which is the defining factor in their common classification.
Popular varieties, including Impatiens walleriana and New Guinea Impatiens (Impatiens hawkeri), are sensitive to cold temperatures and will die when exposed to frost. A temperature drop below 50°F (10°C) causes stress, and the first hard frost will kill the entire plant. This lack of cold tolerance means that outside of tropical climates, the plant cannot survive the winter outdoors.
Growing Impatiens in Colder Climates
Because of their frost sensitivity, the vast majority of gardeners in temperate regions treat Impatiens as seasonal annuals. Cultivation involves planting them outdoors only after the danger of the last spring frost has passed. Planting occurs when soil temperatures have warmed consistently, ensuring the tender roots are not damaged.
Throughout the summer, Impatiens require consistent moisture and thrive in shaded conditions, mimicking their tropical origins. They provide continuous, profuse blooms until the end of the season. The single-season management ends when the first hard frost of autumn kills the plant, requiring its removal from the garden.
Overwintering Impatiens Indoors
Gardeners can treat Impatiens as the perennial they are by moving them indoors before the first frost. This technique extends the plant’s life beyond the outdoor growing season.
Whole plants can be dug up, pruned back by up to half their size, and potted into well-draining soil. Alternatively, new plants can be started by taking cuttings in late summer or early fall, which requires less indoor space than mature plants. Cuttings of about four inches should be taken, the lower leaves removed, and then rooted in water or a sterile medium.
Once indoors, Impatiens require bright, indirect light and temperatures consistently above 55°F (13°C). Water must be reduced significantly, and fertilization should be suspended until late winter to encourage a semi-dormant state.