What Temperature Is Good for Flowers?

Hardiness Growing Zones

• North America is broken down into hardiness growing zones based on average high and low temperatures. When planting outdoor annuals and perennials, first determine the growing zone you live in. Then plant only annuals and perennials that are well-matched for your growing zone.

Flowers Suitable for Hot Climates

• The following annuals generally do well in dry hot climates once their roots are established: African Daisies, Portulaca, Cosmos, Zinnias, Dusty Miller, Calliopsis and Verbena. Other annuals that do well in hot temperatures, but that require more water, include: Dahlias, Flowering Tobacco, Joseph's Coat, Morning Glory, Salvia and Mexican Heather. Even drought tolerant plants need water during extended hot, dry weather. The best time to water plants is early in the morning or in the evening when temperatures are cooler than at mid-day.

Flowers Suitable for Cool Climates

• If you live in a climate subject to cool weather, such as growing zones 3 through 8, you will want to plant your flowers accordingly. Examples of hardier flowers that do well in cooler temperatures are: Snapdragon, Bachelor's Buttons, Pansy, Forget-Me-Not, Sweet Pea, Alyssum and Nasturtium. Many annuals suited to cool climates bloom earlier than hot weather annuals.

Cut Flowers

• When you cut flowers to bring inside, temperature plays an important role when it comes to the duration of blooms. Once you cut the stems of your flowers, put them in water as soon as possible to keep air from blocking cells and preventing water from moving up the stem. If the flowers remain out of water for even a few minutes, re-cut the stems under water. According to horticulturist Mary H. Meyer at the University of Minnesota, the temperature of the water you initially put the cut flowers in should be 110 degrees Fahrenheit. Then place the flowers in a cool location for one or two hours. The combination of the fresh cut stems along with warm water, preservative and cool temperatures causes water to move quickly up the stems, resulting in maximum water absorption and thereby extending the life of the cut flowers as long as possible.

Considerations

• If you live in a cool growing zone and plant hardier flower varieties, many will withstand a light frost during spring and fall nights. But you should take extra precautions when the weatherman predicts a cold clear night with a thick frost. In such cases, cover flowers with newspapers, plastic tarps, sheets or other light bedding. Remember to remove the protection the next morning in order to prevent over-heating from the sun.