Helpful Information About USDA Hardiness Zones

When adding plants or trees to your landscape or yard, it is important to evaluate whether a particular plant will do well in the spot you have picked out for it.  Plants are living things that are sensitive to the environment.  Not every plant or tree will thrive in every location.  One element of the environment that can have a significant impact on plants is temperature.  Knowing your hardiness zone can help you assess the compatibility of a tree or plant with your location.

What Are USDA Hardiness Zones?

The USDA has divided the country into 13 hardiness zones.  These zones have been developed to indicate the average lowest temperature for a specific location based on historic temperature data.  Each zone (Zones 1 through 13 from coldest to warmest) represents a 10-degree temperature range of the average minimum temperature.  The zones are further divided into A (colder) and B (warmer) subdivisions.

Indianapolis and the surrounding central Indiana area fall in Zones 5B and 6A. Zone 5B has an average minimum temperature between -15 and -10 degrees Fahrenheit.  Zone 6A has an average minimum temperature between -10 and -5 degrees Fahrenheit.  Visit the USDA website to view a detailed map and find the hardiness zone for your zip code.

Why Do Hardiness Zones Matter?

Is it important to know your hardiness zone?  If you plan to do any landscaping or planting on your property, it definitely is important.  The hardiness zone tells you how cold you can expect temperatures to get on the coldest days of winter.  Temperature is one component of the climate that can have a serious negative effect on plants.  All trees and plants have a range of temperatures which they can tolerate.  A tree or plant that experiences temperatures outside of that range may even die from the exposure.  You should only plant those trees and plants that can tolerate temperatures expected in your hardiness zone.

How Can Hardiness Zones Help You Plant Smarter?

The hardiness zone is very important for trees, shrubs, and perennial flowers.  However, for annual flowers, this doesn’t matter.  They cannot survive the colder temperatures of winter and are meant to bloom beautifully for the summer and then die.  However, if you are planting perennial flowers, shrubs, bushes, or trees, you will want them to live through many years.  This means that they must be able to withstand both the warm, sunny days of summer and the bitterly cold days of winter.

Temperature vary greatly from season to season (or even day to day here in central Indiana).  Planting vegetation in the sunny days of spring, it’s hard to remember that the icy days of winter will come eventually.  As you consider what to plant, make sure you investigate your hardiness zone and whether the tree or plant you are considering will thrive there.

Nature can be harsh without protection from the elements.  People live in houses and wear clothes to keep the wind, heat or cold, and precipitation from harming us.  Even animals can move to shelter from storms or extreme temperature.  In contrast, a tree, shrub, or plant must endure nature’s best and worst without the ability to move or cover itself.  Without the ability to protect themselves, plants are very vulnerable to extreme weather.   Fortunately, the USDA hardiness zones can help you determine whether a plant is suited for your location before you plant it.