Sample Landscape Plan for a Coastal Bank with an Existing Seawall

Historically, engineered structures such as seawalls and revetments were built to protect coastal banks from erosion and storm damage. However, these structures can cause serious problems along an eroding shoreline. First, they arrest the flow of sand from the bank to beaches and other properties along the shore—exacerbating erosion problems at these locations. They also deflect waves, increasing erosion in adjacent areas and ultimately undercutting the stability of the structure itself. In addition, these structures can alter groundwater flow and surface water runoff and destabilize the bank and adjacent areas. Because of these problems, the Massachusetts Wetlands Protection Act prohibits construction of most new engineered structures on coastal banks that serve as a sediment source.

For seawalls, revetments, and other engineered structures that do exist in Massachusetts, plants can be used around the structures to help uptake water, control runoff, and buffer storm waves to help prevent further erosion and to protect vulnerable areas. Plants will also help beautify the area, provide wildlife habitat, and filter pollutants before they reach the ocean.

The landscape plan for coastal bank with an existing seawall provided below incorporates a variety of native grasses, perennials, groundcovers, and shrubs that will enhance the property. The deep-rooting fibrous grass, switchgrass, was recommended to help control channelized runoff that could cause erosion. Pennsylvania sedge is used throughout the site as a substitute for lawn grass, as a durable erosion-resistant pathway to the stairway, and for low-maintenance accents in other areas of the garden. Native shrubs and perennials are used to screen the seawall, absorb stormwater runoff, and provide berries and shelter for wildlife. The second illustration, the landscape profile, depicts the landscaped yard as viewed from the house looking toward the seawall.

On the landscape plan below, you can move your cursor over each plant icon to find its common name, or you can click on the icon to find a photograph and a complete description of the plant. You can also see the plant list below for a complete list of all of the species used within the plan.

Landscape Plan for Coastal Bank with an Existing Seawall

Landscape Profile for Coastal Bank with an Existing Seawall

Plant List for Landscape Plan for Coastal Bank with an Existing Seawall

Plant icon	Botanical name	Common name	Height	Value
Perennials and grasses
	Carex pensylvanica	Pennsylvania Sedge	6-12"	Low, clump-forming, grass-like perennial with pale-green arching leaves and a cluster of brown seed capsules high on the stem. The grass spreads quickly, grows well in sun or shade, and effectively binds the soil with its dense roots.
	Eurybia spectabilis	Eastern Showy Aster	1-2’	A purple-flowered, short-stemmed aster that is easily cultivated and makes a showy display in late summer. This perennial herb spreads and forms clones by rhizomes.
	Panicum virgatum	Switchgrass	3-6’	Valuable perennial grass with deep-rooted, rhizomatous roots, and a tolerance for both drought and moist soils. This grass is an ideal soil stabilizer.
Shrubs and groundcovers
	Ceanothus americanus	New Jersey Tea	3-4’	A deciduous shrubby perennial that grows in full or partial sun and average to slightly dry conditions. Cylindrical clusters of tiny, fragrant, white flowers arrive in the late spring and later turn to fruits. This plant adds nitrogen to the soil.
	Comptonia peregrina	Sweet Fern	2-4’	A spreading, colonizing nitrogen-fixing plant with slender upright stems with foliage appearing similar to fern fronds, which are fragrant when crushed. This shrub is useful as a ground cover for erosion control and species diversity in sterile, sandy soils
	Hippophae rhamnoides	Common Sea-Buckthorn	20’	A deciduous shrub or small tree with branches that are dense, stiff, and thorny—making it a good barrier hedge. Its dense growth also helps stabilize steep slopes and provides a wind break. Colorful berry clusters are retained through winter. (Native to Canada.)
	Rosa virginiana	Virginia Rose	2-6’	A shrub with many spreading branches, thorny stems, and pink flowers that bloom from June to August. Virginia rose is good for attracting wildlife due to its edible rose hips and flower petals, and thick cover. (Native to southern United States.)
	Vaccinium angustifolium	Lowbush Blueberry	6”-2’	Hardy, low-growing deciduous, twiggy shrub with urn-shaped white flowers and bluish-black edible fruits that matures in mid- to late-summer.

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