What to Do if Pansies Stop Blooming

Soil Moisture

• Lack of water can quickly cause pansies to wilt and flower poorly. The plants may also start to turn brown or yellow as drought stress weakens them. Monitor the moisture in the soil, especially during dry or warm weather. Pansies grow best when the soil remains evenly moist to a 6-inch depth. If the top 1 to 2 inches of soil dries, it's time to water the pansies. Supply the pansies with about 1 inch of water weekly from irrigation or rain, which moistens the top 6 inches of soil. Spreading a 2-inch thick layer of mulch over the soil helps retain moisture, which reduces wilting from water stress.

Pruning

• As the season progresses, pansies can begin to develop weak, leggy stems and sparse flowers. The dead blooms also begin to set seed, which signals the plant to stop bud formation. Cutting back the pansies by about half their height removes the old spent blooms and weak stems. The plants usually respond by sending up new, more compact foliage covered in new flower buds. An application of 1/2 pound of 5-10-5 fertilizer to every 50 square feet of garden after pruning further encourages full growth and flowering. Sprinkle the fertilizer around the plants, and water it into the soil.

Temperature

• Pansies don't tolerate heat and often stop blooming as temperatures heat up above 65 degrees Fahrenheit. Increased watering during warm periods can help avoid temperature induced-drought stress, and the pansies may recover once the temperatures cool. Mulch helps keep the soil cool, increasing the chances of recovery. Often, pansies die in summer and require replanting in fall. You can provide the plants with afternoon shade, which may reduce flowering but increases heat survival. Prolonged frost can cause wilting and possible plant death.

Pests and Diseases

• Although pansies usually resist most diseases and pests, problems can still occur. The stress of the disease or infestation may cause the pansies to flower poorly. Overhead watering makes pansies more susceptible to fungal problems. Proper watering and fertilization that keeps the pansies healthy helps them resist infection, but it's better to rotate the pansies to a new bed each year to further prevent both disease and insect problems. Trim out stems with fungal growth to prevent it from spreading to healthy plants and buds. Check the foliage regularly for aphids, spider mites and other pests that may weaken the pansies so that they don't bloom. You can control most pests by spraying them with a ready-to-use insecticidal soap. These soaps require reapplication every three to five days until the pests are gone.