What are the best plants to prevent and stop erosion on a steep river bank?
Question:
What are the best plants to prevent and stop erosion on a steep river bank?
Answer:
Erosion is a major environmental, structural, and ornamental problem, and we salute your efforts to mitigate it on your riverbank!
In general, you’re seeking two things in preventing erosion: 1) canopy cover to prevent rainfall from directly striking sloped soil, and 2) a strong plant root system to bind the soil. Generally speaking, a horizontally spreading network of fibrous roots works better than plants with deep taproots. If you’re interested in how water erosion occurs and how various root structures interact with it, you can spend a rainy afternoon consulting the Oklahoma State University resources for Using Vegetation for Erosion Control. A slightly more lay-friendly resource from University of Delaware Extension discusses the phenomenon, as well as suggesting other mitigation strategies for controlling erosion.
Your site conditions (sun, soil condition, soil wetness) will dictate to a large extent what plants will thrive there, but for a riverbank, you’re probably looking for quick, inexpensive, and effective over an ornamental investment–another reason for low, spreading covers as opposed to larger trees and shrubs. So you want something like a grass or fern, which will spread and create a dense mat of roots near the surface. The Maine DEP Buffer Handbook Plant List was developed in conjunction with the UMaine Cooperative Extension and has a wealth of information on sturdy, low maintenance, mostly native species for planting in buffer zones (including embankments). The groundcover section begins on page 29 and will give detailed information on selected plant environmental needs, as well as their general growth habit and utility in the landscape. If you would like to invest in more showy plants, there are plenty of options for that as well.