While most summer-blooming annuals require several hours of bright sunlight every day, impatiens are one of few annuals that thrive with little light. Although impatiens are low-maintenance plants, proper watering is critical as impatiens have fleshy stems that wilt when the plants become too dry. Without water, impatiens become stressed and blooming decreases.
Impatiens thrive in moist soil, but it's critical that the soil drains well. Although impatiens wilt in dry soil, they may rot and die in wet, soggy soil. Proper drainage is just as important for impatiens planted in containers. Containerized impatiens must be planted in a pot with a drainage hole. Use a good quality, peat-based potting mixture, as good quality potting soil retains water longer than poor quality potting soil. Improve drainage by using a mixture of half potting soil and half perlite.
Watering Impatiens in Flower Beds
As a general rule, impatiens planted in flower beds benefit from watering once every week. Water deeply enough to saturate the roots. During periods of hot, dry weather, impatiens may need water more frequently. If the top of the soil feels dry or if the plant begins to wilt, water immediately. Impatiens do best when watered at the base of the plant so the foliage remains dry. If you use a sprinkler, water in the morning so the foliage has plenty of time to dry before evening. If foliage is wet during the cooler evening hours, the plant is more susceptible to fungal disease and other problems caused by excessive moisture.
Impatiens in Containers
Impatiens planted in pots require water more frequently, as potting soil in containers dries quickly. Check the impatiens daily and water whenever the top of the potting soil feels dry. During hot, dry weather, impatiens may require water twice daily. Never allow the potting soil to dry completely.
Impatiens don't do well in full sunlight, nor do they thrive in full shade. Locate impatiens where the plants are exposed to morning sunlight. Alternatively, plant impatiens in partial shade or filtered light. Avoid placing impatiens in afternoon sunlight, as the intense light will fade the colors and may harm the plant. The brighter the sunlight, the more water is required.
Cut impatiens stems down to about 3 to 4 inches if plants begin to look spindly during midsummer. Pinching removes unattractive foliage and produces a flush of new growth that lasts until the end of the blooming season. Fertilize impatiens in a flower bed every month, using a general purpose water-soluble fertilizer. Alternatively, mix a time-release fertilizer into the soil at planting time. Use a water-soluble fertilizer for containerized impatiens every other week. Apply fertilizer according to the manufacturer's recommendations.