Impatiens are beloved for providing vibrant, season-long color in shaded garden areas. The two most common types are Impatiens walleriana (Busy Lizzie) and New Guinea Impatiens (Impatiens hawkeri). Although these plants are technically tender perennials native to tropical and subtropical regions, their sensitivity to cold means they are universally cultivated as annuals in temperate climates.
Impatiens: Annual Treatment vs. Perennial Reality
Impatiens are genetically programmed to live for multiple years, classifying them as perennials in their native environment. However, their perennial lifespan is abruptly cut short by minor drops in temperature. They struggle when temperatures fall below 50°F and are killed by the first hard frost.
For the average gardener, the plant’s lifespan is defined by the growing season, usually lasting between four and six months. They are planted outdoors after the last spring frost and bloom continuously until the first frost of autumn. Outside of USDA Hardiness Zones 10 and 11, where temperatures remain consistently above freezing, impatiens function entirely as a single-season annual. Their short seasonal life in colder climates is due to succumbing to environmental conditions they cannot tolerate.
Maximizing Seasonal Bloom Duration
To ensure impatiens last and bloom profusely from spring until the first cold snap, providing the proper environment is necessary. Impatiens thrive in partial to full shade; I. walleriana varieties especially need protection from intense afternoon sun. Planting them in a location that receives filtered light or morning sun prevents scorching and reduces stress.
Consistent moisture is the most important factor for maximizing seasonal performance, as impatiens are not drought tolerant. Their shallow root system requires the soil to remain evenly moist but never waterlogged. If the plants dry out, they will wilt dramatically and may drop leaves. Those planted in containers or hanging baskets often require daily watering, particularly when temperatures exceed 85 degrees Fahrenheit.
To support continuous bloom production through the entire season, regular nutrient application is beneficial. Incorporating a slow-release granular fertilizer into the soil at planting time provides steady nourishment. For container plants, applying a water-soluble fertilizer every two weeks during the growing season ensures they maintain vibrant color and foliage.
Techniques for Overwintering
Making impatiens last beyond a single season involves bringing them indoors to shelter them from freezing temperatures, treating them as temporary houseplants. This transition must happen before nighttime temperatures consistently drop below 50°F, ideally when they are still in the 60s, to prevent cold stress. Before moving them inside, inspect the foliage thoroughly for common pests like spider mites or aphids that could spread to other indoor plants.
One method is to keep the entire plant by pruning it back by up to half or two-thirds to a manageable size. The potted plant should be placed in a location receiving bright, indirect light, such as a sunny, draft-free window. Indoor care requires a significant reduction in watering frequency and the cessation of fertilization until late winter or early spring.
A more space-efficient option is to take stem cuttings in late summer or early fall. Healthy stem tips, four to six inches long, should have the lower leaves removed and can be rooted in water or a well-draining potting mix. Once roots are about a half-inch long, the new plants can be transferred to small pots and kept in a bright indoor spot at a moderate temperature (60°F to 65°F). These rooted cuttings serve as starter plants to be moved back outdoors once all danger of frost has passed the following spring.