The problem
Rain is natural. Before we built roads and buildings, it would fall on deep-rooted native plants that helped it infiltrate into the ground, to be naturally cleaned and cooled before entering the water table. As we’ve developed the landscape, we’ve also dramatically altered the path those raindrops follow. Now they fall on roofs, continue over driveways and lawns, down sidewalks, streets and other impervious surfaces. Rain turns to runoff, picking up pollutants all along the way before entering storm drains that lead to nearby bodies of water. Over half of Minnesota’s lakes, rivers, and streams are impaired, and runoff is a major contributor.
A solution
Blue Thumb–Planting for Clean Water looks for solutions by mimicking the historic hydrology of undeveloped land; specifically, by helping rain filter into the ground close to where it falls, rather than running off the land and carrying pollution into the water. We can achieve this by shaping the land to divert and collect water (as in the basin of a raingarden), and covering it in deep-rooted native plants that slow down, soak up, and infiltrate runoff. This also reduces the wear-and-tear of our aging storm sewers, and helps protect low-lying neighborhoods from flooding. As we see more and stronger rains year after year, this work is only becoming more important.
Hundreds of years ago, the United States was covered in “native” plants—the grasses, foliage, and trees indigenous to our country—before modern settlement disturbed their natural habitat. Native plants differ from non-natives because of the complex relationships they’ve developed over thousands of years with other local organisms, acting as critical components in maintaining nature’s delicate balance. Many species occurred across relatively wide ranges of geographic, climatic and environmental conditions. Sub-groups became adapted to various local conditions within these wider ranges. These are called “local ecotypes”. It is desirable to use the best adapted plants for a landscape project. Local ecotype native plants are well-adapted to local conditions. Blue Thumb projects using native plants focus on local ecotypes—plant material propagated from original sources no farther than 200 miles (300 for trees and shrubs) from the project.
While Blue Thumb began by using native plants to help clean water, we recognize that native plants are so much more than their deep roots. They form the base of the food web that supports native wildlife like bees, butterflies, and birds. Iconic species like the Monarch butterfly and the Rusty Patched bumble bee are threatened by the loss of habitat, but they are not alone. Just in Minnesota, many once-common pollinators are now rare or gone, primarily because they cannot eat pavement, turf grass, or corn. Around the country, we’ve lost 25% of our birds population in the last 50 years, in part because the insects they depend on are also disappearing. Native plants feed and shelter the natural world. By choosing to reintroduce them in even a small part of your yard, you can help reverse this narrative of decline.
