How deep should erosion control plant roots grow?

Root depth dramatically affects erosion control effectiveness. Plants adapt specialized root systems to threats from erosion. Surface erosion is mitigated with shallow-rooted mats that bind the surface soil. Steep hills have deep-rooted plants that approximate anchors extending through subsoil layers. Knowledge of these root differences can help when choosing plants. Match the root form to the specific soil erosion problem you have.

Before planting, assess your erosion threat. Check your exposed tree roots to see how deep the soil is missing. Dig test pits deep enough to reveal the level of your exposed subsoil. Compare the findings to the depth the roots need to grow. This way, you will not choose any plants that do not have enough soil to penetrate.

Soil types greatly affect the development of roots. Sandy soils permit roots to grow quickly to greater depths. Clay soils retain roots at great depth; therefore, a few plants are developed that are suited to these soils. Clay soils should be enriched with compost before planting deep-rooting species. Roots must be able to reach that depth if the plants are to be properly supported.

Native plants naturally reach their full depths. Their roots are adapted to local geology. The Wild Indigo sends its tap roots down to the water, which is 10 feet beneath the surface. The rhizomes of the Switch Grass will penetrate 7 feet in 2 years. This is greater depth and rapidity than that of the non-natives.

Techniques for planting increase root growth. Allow plants adequate spacing for their root systems to expand fully. Water infrequently but deeply, enabling the roots to grow downwards. Avoid fertilizers that cause roots to grow at the soil surface. Proper practices ensure that roots grow to sufficient depths.

Read the full article: 10 Best Erosion Control Plants for Your Landscape