Impatiens (Impatiens walleriana) provide color in shaded garden beds. These delicate flowers also grow well in hanging baskets and containers, where their pink, blue, purple, red or white blooms spill over the sides. Most impatiens are grown as summer annuals, although they are perennial in U.S. Department of Agriculture plant hardiness zones 10 and 11. Insects, disease and cultural problems can cause shriveling and premature death, but it's usually avoidable if you treat the problem promptly.
Heat and Sun
Too much heat and sunlight causes impatiens to quickly shrivel and die. These plants thrive and flower profusely in shaded locations. A location with light, dappled shade all day protects the plants from heat and sun wilting. Most impatiens can also tolerate morning sunlight, as long as they receive shade from intense afternoon sun. Move the impatiens to a shadier location or add a trellis to shade the plants in a garden bed if sun exposure is causing wilt.
Impatiens require consistently moist soil to grow well. As the soil dries, the plants begin to shrivel and they eventually die. Soil rich in organic matter retains sufficient moisture, so amending the site with compost before planting can help prevent water stress. A 2-inch layer of mulch spread over the soil also helps avoid dry soil. Provide impatiens with about 1 inch of water a week, or enough water so the top 6 inches of soil remains moist. Container-grown impatiens require more frequent watering and need watering when the top 1 inch of soil begins to dry.
Downy mildew causes impatiens leaves to curl and shrivel. The first symptom of downy mildew shows as yellow stippling on the foliage or a white growth on the underside of the leaves. As the fungal infection spreads, the leaves begin to curl inward and the plant's growth becomes stunted. Severe infections can kill the plant. Dispose of badly infected plants and prune out infected leaves on otherwise healthy impatiens to minimize the spread of the fungus. Keeping the bed clean by removing all dead plant material also minimizes mildew problems.
Insect pests feeding on impatiens can cause shriveling. Cutworms chew through stems, causing parts of the plant to wilt and die completely. Inspecting the plants regularly and removing the pests by hand can control a minor infestation. A granular insecticide spread around the impatiens can control a more severe infestation. Aphids, mites and other small insects that feed on the sap in the plant's leaves can also cause shriveling, if they are present in large numbers. Applying an insecticidal soap or rinsing the pests off the plants with a sharp spray of water kills these pests.
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