Climate Your Plants
Many plants thrive in Indiana and around the Midwest, but plants from very warm, very cold, or very dry climates may struggle to survive. The Midwest’s plentiful but irregular rainfall, and our four-season climate affect plant growth and survival. Plant tags give you valuable information about a plant, including the hardiness zones in which it will grow. Here are some weather-related issues to consider when selecting and caring for the plants in your landscape:
Know your hardiness zone
The U.S. Department of Agriculture (USDA) has established plant hardiness zones based on a region’s historical average minimum temperatures (see map). For example, zone 4 has average minimum winter temperatures of -20°F to -30°F. In zone 7, the range is 0°F to 10°F. When you buy perennials, trees, and shrubs, the accompanying tag should list the USDA zones in which the plant will grow. Select plants that are hardy to your zone. For example, if you live in zone 5, make sure 5 is in the range listed on the tag. Plants listed as hardy in zones 3-6 or 5-7 will survive in zone 5 areas. Plants listed as hardy in zones 6-9 or 7-9 will find zone 5 areas
too cold and are not likely to survive.
Know the direction of the prevailing wind.
Strong winter winds, often from the west or northwest, can dry out evergreen plants, especially ones with large leaves such as holly and rhododendron. These plants grow best when they are sheltered from the wind by the house or other structures.
Know the plant’s water needs
Although rainfall in the Midwest is often adequate, supplemental water may be needed during a dry summer or fall. This is especially true for newly-installed plants. During warm weather, plants need about 1 to 1.5 inches of water each week (total rain and irrigation), preferably supplied all at one time (see How Much Water?, page 15). After irrigating, check the depth of watering to make sure you have applied enough water to soak 8 to 12 inches into the soil.
In winter, evergreen plants can dry out after the ground freezes and they can no longer take up water. To keep this from happening, water evergreens in summer if it is dry. Continue to water them in autumn if rainfall is inadequate — even as late as November and December — until the ground freezes.