Using native plants to clean up toxic sites
There are several kinds of bioprocesses that use plants to clean up soil toxins (Phytoremediation), but a couple stand out as being more valuable to use by landscape architects and garden designers. Phytostabilization (the immobilization of contaminants by plants) and Rhizosphere Biodegradation (the breakdown of soil toxins by microbes in the soil level called the rhizosphere) are the most applicable for broad use primarily because they are less expensive than other kinds of phytoremediation processes. However, there are other benefits in using these two processes over some of the others, the most important being the link between site cleanup and habitat restoration when native plants are used instead of non-natives.
When phytostabilization is applied soil toxins are ‘locked up’ or stabilized in soil, limiting the spread of the toxic pollutants to other areas. These mechanical and chemical processes can be further enhanced with a well-designed planting plan that creates an extensive and elaborate rhizosphere that can host a variety of toxin destroying microbes. Native plants are most suitable for doing this due to the extensive root systems they have evolved over time to deal with periodic drought conditions. Native plants have also co-evolved with numerous local soil microbes, giving them an advantage over exotic non-natives in creating extensive microbial communities in the rhizosphere. What’s particularly good about combining phytostabilization and rhizosphere biodegradation is that you can use native plants to accomplish both processes. These bioprocesses can be applied to any region of the country by utilizing the local flora and fauna, and in this case the local fauna includes local soil microbes.
Rainscape Design’s native planting plans can be applied in phytostabilization and rhizosphere biodegradation schemes. Our specifications for installation and maintenance of these remediation landscapes are intended to help establish transplants quickly, with beneficial microbes, and create a sustainable nutrient cycle. This nutrient cycle also supports the microbes needed to neutralize toxins in the soil. For more on using native plants for phytoremediation see the following link: Spiraling Roots.