Prevent erosion with vegetation

Anyone who owns property with a bluff or steep hillside knows that erosion and soil stability are real concerns and that options for preventing erosion are limited.

Major structural retaining walls are unsightly, expensive, and involve engineering and permits. Yet doing nothing is also difficult to accept as you watch your property disappear.

Re-vegetation, i.e. planting shrubs and trees, is the other option to help protect your property, according to the Washington State Department of Ecology (DOE).

A DOE article, "Slope Stabilization & Erosion Control Using Vegetation," explains how plants help stabilize a hillside.

"When properly installed and maintained, vegetation can protect slopes by reducing erosion, strengthening soil and inhibiting landslides which increases general slope stability. The use of vegetation to manage erosion and protect slopes is relatively inexpensive, does not require heavy machinery on the slope, establishes wildlife habitat, and can improve the aesthetic quality of the property."

Each hillside and bluff is unique, but the typical revegetation project involves selecting plants — shrubs and small trees — to install a "grid" somewhat like a fishnet to help hold the plants in place, and then planting the selected shrubs and trees.

The goal of the project is for the plants to become established. Their foliage and roots, as well as the grid itself, will improve the situation.

Hillside erosion and instability are caused by many factors.

While it is commonly accepted that vegetation can help protect slopes, there are obviously no guarantees there won't be erosion or instability. There are just too many variables and influences. But an established re-vegetation grid should improve the situation by lessening both surface erosion and shallow earth movement.

Because re-vegetation doesn't include structural improvements or grading, there are little or no permit requirements. DOE does encourage landowners, however, to consult with county government representatives in advance about a project, just to be sure.

DOE has prepared two comprehensive guides to assist property owners.

Both are available online by simply "Googling" their titles:

• "Slope Stabilization & Erosion Control Using Vegetation"

• "Vegetation Management: A Guide for Puget Sound Bluff Property Owners"

A successful re-vegetation effort results in a hillside or bluff that is more stable, less subject to erosion, and better looking. Re-vegetation is supported and encouraged by governmental agencies, and is much less complicated and much less expensive than a retaining wall or other structure.

Re-vegetation is an option that should be considered by any property owner concerned about instability or erosion on their hillside or bluff.

Camano Island resident Vic Malian is a passionate fisherman, outdoor enthusiast and conservation advocate. He is a licensed contractor with a specialty in landscaping for bluffs and hillsides.

Michael S. Gillie is the founder and manager of NurseryTrees.com, LLC, a "re-vegetation" nursery in Snohomish.