Impatiens are popular annuals, cherished for their vibrant, continuous blooms that bring color to shady garden areas and containers. Their ease of care and diverse uses make them a favorite for enhancing various garden settings.
Choosing and Planting Impatiens
Impatiens offer several types, each with distinct characteristics. Impatiens walleriana, also known as Busy Lizzie, is a classic variety known for its prolific flowering and preference for partial to full shade. Direct sunlight, especially harsh afternoon sun, can scorch their leaves and cause wilting. These plants typically grow 6 to 24 inches tall.
New Guinea Impatiens (Impatiens hawkeri) feature larger flowers and often variegated foliage. SunPatiens, a hybrid, tolerate more sun, heat, and humidity, providing continuous blooms. Both New Guinea Impatiens and SunPatiens can handle more sun, performing well with morning sun and afternoon shade, or even full sun if consistently watered. SunPatiens bloom best with at least four hours of direct sunlight daily, though they will still flower in shadier spots. Even sun-tolerant varieties benefit from afternoon shade to prevent scorching and wilting.
Impatiens prefer well-draining, humus-rich soil with a slightly acidic to neutral pH (6.0-6.5). Before planting, amend the soil with compost or other organic matter to improve fertility and drainage. When planting in garden beds, loosen the soil 8 to 12 inches deep. Gently remove the plant from its container, ensuring the top of the root ball is level with the surrounding soil, then backfill and water thoroughly. For container planting, use a high-quality potting mix and ensure drainage holes. Space Impatiens walleriana 8 to 12 inches apart in garden beds to encourage bushy growth.
Essential Care for Thriving Impatiens
Moisture
Consistent moisture is crucial for Impatiens; they are not drought tolerant and wilt quickly if the soil dries. In-ground plants generally require at least two inches of water per week, potentially doubling in hot temperatures. Container-grown Impatiens often need more frequent watering, sometimes daily, especially in warm, windy conditions. Keep the soil consistently moist but never soggy, as both overwatering and underwatering can lead to problems. Watering plants early in the day allows foliage to dry before night, which helps reduce the risk of fungal diseases.
Fertilization
Regular fertilization supports continuous blooming. For garden beds, incorporate a slow-release granular fertilizer at planting or apply a balanced water-soluble fertilizer every two to four weeks. Container-grown Impatiens, due to more frequent watering and nutrient leaching, benefit from more regular fertilization, typically every two weeks, using a balanced liquid feed. Diluting liquid fertilizers to half strength and applying more frequently can yield better results.
Common Challenges and Solutions
Pests
Impatiens can encounter several common pests, including spider mites, aphids, and thrips. Spider mites, indicated by speckled leaves and webbing, thrive in dry conditions; manage with increased humidity, insecticidal soap, or neem oil. Aphids, causing distorted growth and sticky honeydew, can be dislodged with a strong water stream or treated with insecticidal soap. Thrips cause stippled leaves and deformed flowers; monitor with sticky traps or treat with neem oil. Slugs and snails may also cause irregular holes in leaves, particularly in damp environments, and can be deterred with barriers or hand-picking.
Diseases
A significant disease concern for Impatiens walleriana is Impatiens downy mildew (Plasmopara obducens). Symptoms include yellowing leaves, stunted growth, and a white, fuzzy growth on the undersides of leaves, eventually leading to plant collapse. Prevention strategies include planting disease-resistant varieties, providing good air circulation, and avoiding overhead watering. If downy mildew appears, remove and discard affected plants to prevent further spread, as there is no effective cure. Other fungal issues, such as leaf spots or root rot, can arise from overly wet conditions or poor drainage.
Environmental Stress
Environmental stress can indicate care adjustments are needed. Wilting is a common symptom, often due to underwatering or excessive heat exposure. While plants typically recover quickly once watered, consistent wilting can lead to poor flowering. Yellowing leaves can signal overwatering, which deprives roots of oxygen, or a nutrient deficiency. Leggy growth, characterized by long, thin stems with sparse foliage, often results from insufficient light or a need for pruning. Addressing these factors by adjusting watering, improving light, or providing proper nutrients can help restore plant health.
Ongoing Maintenance
Pruning and Deadheading
Regular pruning and deadheading enhance the appearance and blooming performance of Impatiens. Deadheading, which involves removing spent blooms, redirects the plant’s energy from seed production to developing new flowers, promoting continuous color. Pinch off faded flowers just above a healthy leaf or node. Light pruning or pinching back leggy stems encourages bushier, more compact plant growth.
Overwintering
In colder climates, overwintering Impatiens is an option to preserve plants. Potted plants can be brought indoors before the first frost. To prepare, cut stems back to about three inches and place plants in a bright location with reduced watering during winter. Taking stem cuttings in late summer is another viable method; these cuttings can root in water and then be planted in potting mix to grow indoors, ready for transplanting outdoors after the last spring frost.