Pansies (Viola x wittrockiana) are herbaceous, biennial flowers that are commonly grown as annuals in cooler climates. Thanks to their ability to withstand freezing temperatures with protective mulch, pansies are found in U.S. Department of Agriculture zones 1 to 11. Flat, single blooms with five petals appear when temperatures are between 40 degrees and 60 degrees Fahrenheit. More than 300 varieties are available in the United States, with some newer hybrids better able to tolerate heat.
In USDA zones 8 through 11, grow pansies in fall, winter and spring as summer temperatures in these areas are too hot. Start seeds indoors in July or August, and then transplant outdoors in early fall. Pansies often reseed themselves, making it difficult to discern when old plants die and new ones take their place.
The biennial nature of pansies is reflected in the flower’s tendency to go dormant when temperatures fall below 25 degrees Fahrenheit. When not grown as annuals, which die at the end of a growing season, pansy foliage wilts and turns gray-green as a normal defense response to cold weather. Plants can survive short periods of single-digit temperatures if covered with straw or other organic material. Once temperatures warm, pansies continue growing through a second season.
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