Double Impatiens (Impatiens walleriana hybrids) are celebrated for their vibrant, rose-like blooms that thrive in shaded garden spots. These popular flowers offer continuous color from spring until the first heavy frost. Gardeners frequently question whether they should be categorized as annuals or perennials. The classification depends entirely on the climate where the plant is grown. Understanding the botanical classification clarifies why these shade-loving plants behave differently across various regions.
Annuals and Perennials: Understanding the Difference
Plants are generally classified by the length of their life cycle. An annual plant completes its entire life cycle—germination, growth, flowering, seed production, and death—within a single growing season. A true annual is genetically programmed to die after reproduction, regardless of whether it is exposed to frost.
A perennial plant, conversely, is one that lives for more than two years, often returning year after year from the same root system. Hardy perennials are adapted to survive freezing winter temperatures through dormancy, while herbaceous varieties die back to the ground and regrow in the spring. The distinction between these categories is important for predicting a plant’s survival in a given climate.
Double Impatiens: Classification Based on Climate
Double Impatiens are botanically considered “tender perennials,” meaning they possess the genetic ability to live for multiple years. Their native habitat is the tropical and subtropical regions of East Africa, where they survive year-round without interruption. This perennial classification is contingent upon a frost-free environment.
In most of the United States and other temperate regions, these plants are universally grown as annuals because they cannot tolerate cold temperatures. Impatiens walleriana is hardy only in USDA hardiness Zones 10 and 11, where temperatures rarely drop below freezing. Even a light frost can cause the succulent stems and leaves to collapse, killing the plant entirely.
For gardeners living in Zones 9 or colder, Double Impatiens are treated as temporary summer bedding plants. They are purchased in the spring and discarded after the first hard freeze in the autumn.
Methods for Extending Their Life Indoors
Since Double Impatiens are unable to survive cold weather outdoors, gardeners who wish to keep their plants can extend their life by bringing them inside for the winter. This process, known as overwintering, requires careful timing and manipulation of the plant’s environment. The plant must be moved indoors before nighttime temperatures consistently drop below 50°F, which is a key threshold for this tropical species.
One approach is to bring the entire potted plant indoors after cutting it back by about one-third of its size to make it more manageable. Before moving it inside, the plant should be thoroughly inspected for pests like aphids or spider mites, which can easily infest other houseplants during the winter. Once inside, the plant needs a location that provides bright, indirect light, such as a south-facing window, or supplemental light from a grow lamp for 12 to 16 hours daily.
A more space-efficient method is to take stem cuttings in late summer or early fall. To do this, collect six-inch stem sections, remove the lower leaves, and place them in a jar of water or a container filled with a moist, soilless rooting medium. Impatiens root readily, and a rooting hormone is usually not necessary for successful propagation.
Whether overwintering a whole plant or a cutting, indoor conditions must be controlled to maintain health through the dormant season. The ideal temperature range is between 60°F and 75°F, avoiding cold drafts from windows or heating vents. Watering should be reduced significantly, allowing the top surface of the soil to dry slightly between applications to prevent root rot.