Why Did My Impatiens Stop Blooming?

A Problem with Light

• Garden impatiens flower best in filtered or partial shade. If they receive direct afternoon sunlight or otherwise too much sunlight, it affects their bloom color, and their soil tends to dry out. If, however, they are in very deep shade, they can become leggy, or spindly, with fewer leaves and flowers. Although garden impatiens flower best in shade or partial shade, New Guinea impatiens and garden balsam benefit from slightly more sunlight and may even grow well in full sunlight if it is not too hot and water is adequate. Light that is too intense or inadequate negatively affects flower numbers and bloom size.

The Possibility of Disease

• Botrytis blight, or gray mold, caused by the fungus Botrytis cinerea, can affect impatiens and a broad range of other ornamental and crop plants. Botrytis blight, most common during humid weather and in crowded plantings, appears first as brown or gray spots on leaves, flowers, buds or stems; the spots eventually enlarge and become covered with indicative gray spore masses. If the disease affects flower buds, they will fail to open and drop off their plant. Good sanitation practices are crucial to avoid or address problems with this fungus. Pinch off fading flowers, remove fallen plant debris and pinch or cut off all infected flowers, buds and leaves as soon as you notice they are infected. Bag and dispose of plant parts you remove. Also avoid overhead watering or otherwise splashing the plants with water, which spreads fungal spores. Downy mildew, another fungal disease, can affect impatiens in a similar manner and is treated best in the same way as Botrytis blight.

A Water Issue

• Impatiens are very prone to moisture stress. If the soil around impatiens dries out, the plants wilt quickly and lose leaves and flowers. A deep watering of the soil around the impatiens at least weekly is usually necessary; the soil around the plants' roots should be evenly moist but not soaking wet. The necessary frequency of irrigation depends on rainfall, soil type and the amount of sunlight the site receives. Plants growing in containers benefit from watering whenever the soil surface feels dry to the touch. Ensure the containers have plenty of unimpeded drainage holes that permit excellent soil drainage.

The Heat of Summer

• If impatiens exhibit reduced blooming or lack flowers almost entirely and it is the heat of summer, then suspect that the current weather is responsible for the decreased blooming, especially if the impatiens receive some sunlight and no signs of diseases or other site problems are present. Simply continue to water the impatiens about weekly, or as needed, and they should resume flowering when the weather cools slightly.