From a botanical perspective, the question of whether Impatiens are annuals or perennials is not a matter of simple classification for the entire genus. The genus *Impatiens* encompasses over 1,000 species, and their life cycle is fundamentally dictated by their evolutionary adaptation to specific climates. In their native tropical and subtropical habitats under the canopies of forests in regions like East Africa and Southeast Asia, these plants are true herbaceous perennials. They lack the woody tissue of shrubs but possess root systems that are genetically programmed to survive for multiple growing seasons, going through cycles of growth, flowering, and dormancy without dying.
The defining factor that changes their status in cultivation is cold tolerance. Impatiens are extremely sensitive to frost and freezing temperatures. Their cell structure, optimized for stable, warm environments, cannot withstand the formation of ice crystals, which rupture cell walls and lead to plant death. The USDA Plant Hardiness Zone Map, which categorizes regions by their average annual extreme minimum winter temperature, provides the key to understanding their behavior in your garden. Most common garden Impatiens (*Impatiens walleriana* and hybrids) are only cold hardy in Zones 10-11, where temperatures rarely, if ever, dip below 30°F (-1°C) to 40°F (4°C). In these zones, they will perform as the perennials they are genetically.
For the vast majority of gardeners in temperate climates across the United States (approximately Zones 2 through 9), Impatiens are functionally and horticulturally treated as annuals. This means they complete their entire life cycle—germination from seed, vegetative growth, flowering, setting seed, and death—within a single growing season. When the first frost arrives in autumn, the plants succumb entirely. However, it is crucial to understand that this death is not due to the completion of a biological imperative to die after flowering (a true annual trait like in wheat or marigolds) but is an exogenous death caused by an external environmental factor (cold) that their physiology cannot survive.
A prominent group within the genus, New Guinea Impatiens (*Impatiens hawkeri*), shares this same climatic limitation. While often more sun-tolerant and featuring showier foliage than their common cousins, they possess the same fundamental sensitivity to cold. They are also perennial in their native habitat and in USDA Zones 10-11 but are universally grown as annuals elsewhere. Their slightly thicker stems and leaves do not confer any significant additional frost resistance, and they are killed by freezing temperatures just as readily.
