Pansies are cool weather flowers. In areas where winter temperatures do not drop much below 20 degrees F, pansies will live through the winter. For this reason, some people think of pansies as perennials; however, it is necessary to grow new plants each year. Start pansies indoors early and set them out as early as the ground can be worked in the spring. Or plant pansy seeds in early autumn for late fall and early spring flowers. No matter when you plant pansies, most varieties do not tolerate summer heat well. If your pansies wilt and become distressed during the summer heat, you can revive them for more flowers in the fall.
Remove the flower heads as soon as they fade. This keeps the pansy from using energy to make seeds so it can focus on producing more flowers and a strong root system. Trim back leggy plants to make them more compact. This also encourages new flowers and roots.
Move container grown pansies into the shade as the seasonal temperature rises. Stress from summer heat causes pansies to decline rapidly. Water them frequently, and do not allow the soil to dry out. Besides meeting their need for moist soil, the water lowers the soil temperature. Use mulch to keep the soil cool and help retain moisture.
Water pansies throughout the summer, whether they are in the ground or in containers, but temporarily stop fertilizing them during the hot summer. Begin feeding your pansies again with a balanced water soluble organic fertilizer in late summer. Use a diluted solution once or twice a week at first to get them started. As the seasonal temperatures continue to cool, the new feeding regimen will revive your pansies, and they will begin to produce flowers two to three weeks later.
Plant pansy seeds in the ground in September, and they will bloom in November and perhaps into December. Do not pull up these plants when they succumb to the cold. Instead trim them back and cover them with mulch. As soon as the weather begins to warm up the following spring, pull back the mulch. Fall planted pansies will revive as soon as they get some warm spring sun. They will begin to bloom again in March or April, depending on your location.