You did everything right. You hired a reputable landscape designer who worked closely with you to make sure the project met all your expectations. They tested and amended the soil, planted your trees and shrubs at the correct grade in the proper location, mulched properly and gave you clear directions on watering—which you followed! The landscape was picture perfect. Two years later, your trees start dying. You wonder, “What went wrong?” Could it be it was not something you did or didn’t do? Could it be that the tree wasn’t ready to live in northern Illinois? Maximizing the benefits of trees transplanted into a landscape is possible only if they survive and thrive. Plants have to be well adapted to the growing zone in which they will be transplanted.

The National Arboretum in Washington D.C. sets the standards for hardiness zones in the U.S. These standards group plants into zone specific growing areas based on plant tolerances. The ability of a plant to be successfully grown in an area is determined by these preset seasonal and climatic growing requirements as well as the site-specific environment.  Some requirements are obvious; such as plant preferences for sun, soil, water and air. Other conditions are much less obvious, such as day length, altitude, heat, temperature, pH, ozone and plant origins. It is important to know in what zone plants originated. Different ecotypes of the same plant often tolerate different ranges of temperature and moisture extremes. “Although plants may tolerate some extraneous elements and compounds, every plant species and cultivar has well prescribed limits.”

This rule of thumb applies to both native and cultivated plants. Though a cultivar is a clone (and technically, can be grown wherever conditions meet the predetermined limits of that plant), they will not simply ‘adjust’ to the extremes of another zone. A northern-grown sugar maple is acclimated to this growing region and will withstand our conditions, unlike a sugar maple from a much warmer zone in the southern edge of the range. Many cities are already implementing standards to take this into account. For example, the City of Chicago planting guidelines require plants come from a 200-mile radius of the city.

Chicagoland Grows® Miyabe Maple

Plants that thrive in our growing range also support a wealth of beneficial insects, soil organisms, animals, birds and human habitat specific to our zone. Plants from our own growing zone generally require less fertilizer (less ground water pollution), less maintenance (fewer replacements), less water consumption (more conservation), reduce carbon footprint (less air pollution), reduce shipping costs (increase efficiencies) and support the local economy (your community). All of these benefits come in the form of dollars saved in the long run, not to mention healthier, stable, long-lived plants. A plant that thrives will reap benefits in beautification as well as resource and energy savings.

A well-thought landscape can increase the home value and reduce energy costs. Even in a down housing market, landscaping is a sensible investment. In fact, planting trees is the only investment that really grows.
     
How do you know where your plants are from?  Ask! You can ask your landscaper or garden center where their plants came from and try to purchase from those nurseries that grow locally and buy locally.   

You can learn more about locally grown plants, and plants developed specifically for this growing region through the Chicagoland Grows Plant Introduction Program. Chicagoland Grows® is a partnership among the Chicago Botanic Garden, the Morton Arboretum and the Ornamental Grower’s Association of Northern Illinois (OGA), a network of wholesale nurseries located in northern Illinois.
    
Chicagoland Grows® is an innovative plant introduction program developed to promote the use of new plant cultivars that are well-adapted to the growing conditions of the Upper Midwest.  Plants are selected, tested and evaluated under many conditions before they are introduced and marketed in the zone-appropriate regions for which they have been developed.

—Mary T. McClelland
 
For more information, visit these websites:
www.ogaoni.com
www.chicagolandgrows.org
www.mortonarb.org
www.usna.usda.gov