Coastal Bank

Many of the coastal banks in Massachusetts are landforms deposited by the last glaciation. Some coastal banks are not glacial in origin, including bedrock banks or sediment banks that were deposited prior to the glaciers (though both may have subsequently been eroded, weathered, or displaced by glaciers). Given their origin, coastal banks may be composed of various materials, ranging from solid bedrock to sediments consisting of silt, sand, or unconsolidated rocks and soil. The banks that are unconsolidated and are exposed to wave and wind energy are subject to erosion. Landscaping these areas can:

Selecting plants that are appropriate for the rugged conditions of a coastal bank will help ensure that the landscape serves these benefits. See the sample landscape plan for a coastal bank and the sample landscape plan for a coastal bank with an existing seawall for examples of appropriate plants and effective landscape design approaches.

NOTE: Before bringing in that backhoe (or even a shovel), you will need to contact your local Conservation Commission to determine if a permit is necessary. Please see Coastal Landscaping - Do You Need a Permit? for more information.

Planting to Help Reduce Erosion and Stabilize Coastal Banks

The stability of coastal banks made up of loose materials such as sand, rocks, or soils can be greatly improved by plants. A thickly planted area can prevent the surface runoff of rainwater or snow melt from creating gullies or ruts in the bank. Plants also absorb the water that falls to the ground or enters the groundwater, reducing the seepages within a bank that could cause landslides, slumps, or a bank collapse. Rows of thick drought-tolerant grasses planted across the face of a bank create a natural barrier that slows water runoff and allows sediment to be deposited, allowing the bank to gradually build up. (Be sure to avoid planting rows of plants in such a way that they channel the water downhill and increase erosion.) A strip of dense shrubs or perennials or deep grasses along the top of a coastal bank can also limit access and foot traffic that may otherwise aggravate erosion or be a safety concern.

Grasses that are extremely tolerant of the salt spray and exposure to wind and waves, such as American beachgrass (Ammophila breviligulata), can help build up windblown sediments on the face of banks or bluffs, and effectively bind the soil with their thick, fibrous root systems. The roots of beachgrass can establish themselves quickly, while allowing other plants to take hold. Other native grasses and smaller low-growing shrubs, such as switchgrass (Panicum virgatum), bearberry (Arctostaphylos uva-ursi), and common juniper (Juniperus communis), can be grown on the slopes of banks—their root structure and surface area also provide stability. Larger native shrubs, such as bayberry (Myrica pensylvanica) and beach plum (Prunus maritima), are also good choices for exposed areas of a coastal bank since they are hardy and tolerant of salt spray and drought. Trees, such as black cherry (Prunus serotina), pitch pine (Pinus rigida), Eastern red cedar (Juniperus virginiana), and white oak (Quercus alba), may be beneficial for stability, since their root structures are either deep or spreading. However, locating trees on banks should be done carefully to ensure that the weight of the tree does not contribute to bank instability. In general, trees should be placed on lower slopes or set back from steep slopes. On steep slopes where planting is difficult, biodegradable erosion fabric, such as coconut fiber or coir mesh, may be used as a temporary erosion control effort, before plants take root.

Plants vs. Engineered Structures

For property that is experiencing serious erosion, rather than installing a hard coastal engineering structure (such as a seawall, riprap, or bulkhead), consider planting a protective vegetated cover on the bank. In most cases, engineered structures are prohibited in Massachusetts because they stop the movement of sediment in the overall system and reflect waves, both of which can damage other properties. Plantings, however, can buffer wave energy while maintaining natural sediment transport, and are therefore allowed under state and local wetlands protection regulations . Plantings are also substantially less expensive and more aesthetically appealing than structural measures. And while any form of bank stabilization interferes with the natural processes of erosion, plants are a more natural stabilizer. But, they need to be live plants with roots—brush, vegetative debris, discarded Christmas trees, and other materials act to limit the growth and establishment of plants, do not help bind soils, and therefore should not be placed on top of (or on the face of) a coastal bank.

The seawalls, revetments, and other engineered structures that do exist in Massachusetts pose a landscaping challenge. The build-up of water immediately landward of the structure can cause sinkholes and slumping, channelization of runoff can occur at the structure’s edges, and waves can reflect off the structure—damaging surrounding areas. Plantings are a natural stabilizer of coastal banks and can therefore be used in conjunction with an existing seawall to prevent further erosion and help protect vulnerable areas

Planting to Enhance Wildlife Habitat and Aesthetics

To enhance the aesthetic and wildlife values of a coastal bank, you may choose to plant species that form a shrub thicket mimicking a natural rocky headland environment or a stable sand embankment. Dense patches of shrubs and trees, such as Eastern ninebark (Physocarpus opulifolius), Eastern red cedar (Juniperus virginiana), black cherry (Prunus serotina), beach plum (Prunus maritima), red chokeberry (Aronia arbutifolia), highbush blueberry (Vaccinium corymbosum), Virginia rose (Rosa virginiana), and bearberry (Arctostaphylos uva-ursi), provide nesting areas for various bird species, including northern harriers, northern towhees, and song sparrows, as well as foraging areas for many mammal species. Since many of these plants have edible fruits, these shrublands are heavily used during fall migrations for birds. To beautify the landscape, you can include flowering perennials, such as red columbine (Aquilegia canadensisis), pink tickseed (Coreopsis rosea), and Eastern showy aster (Eurybia spectabilis), as well as visually appealing grasses, such as little bluestem (Schizachyrium scoparius), wavy hairgrass (Deschampsia flexuosa), and purple lovegrass (Eragrostis spectabalis).

Selecting Plants

Very few species of plants are resilient enough to withstand the rugged conditions on a coastal bank. Dry, sandy soils and exposure to salt and wind make a very specific niche for only the hardiest of plants to survive. Picking the right plants will save you time and money and will better serve the environment. Certain native species have survived and thrived in this environment for years and are therefore the obvious choice for planting.

The following lists include plants for more exposed areas and more sheltered areas of the coastal bank. Additional information is provided for the plant species listed below that are linked to the Plant Highlights and Images page . CZM recommends the use of natives wherever possible, and the vast majority of the plants listed below are native (which, for purposes of this website, means that they occur naturally in eastern Massachusetts). Certain non-native species that have specific coastal landscaping advantages and are not known to be invasive have also been listed. These plants are labeled as “not native” (with a link to the definition of that term) and their state or country of origin is given in parentheses.

Coastal Bank Plant List

Plant List for Exposed Areas of a Coastal Bank

The top and face of the coastal bank is where the landform is most exposed to wind, salt spray, and storm waves. The plants listed below are appropriate for the rugged conditions of an exposed coastal bank.

Grasses, Perennials, and Vines
Shrubs and Groundcovers
Trees (only on low slopes or set back from the top of the bank)
Plant List for More Sheltered Areas of a Coastal Bank

Areas landward of the top of coastal bank are more protected from wave action, but may still be significantly affected by wind and salt spray. The plants listed below, as well as those listed above for exposed areas of a coastal bank, are appropriate for these more protected areas of the coastal bank.

Grasses, Perennials, and Vines
Shrubs and Groundcovers
Trees

For more information about many of the plants that are listed above, visit the United States Department of Agriculture (USDA) Natural Resources Conservation Service's (NRCS) PLANTS Database, the University of Connecticut (UConn) Plant Database of Trees, Shrubs, and Vines, and the Lady Bird Johnson Wildflower Center Plant Database. The specific native status of each plant was determined by using The Vascular Plants of Massachusetts: A County Checklist available through the Natural Heritage and Endangered Species Program .

A native plant species is a plant that is considered indigenous and naturally occurring to the region since pre-Colonial times (before 1500) or arriving more recently without human intervention. For purposes of this website, a native plant is one that occurs naturally in eastern Massachusetts.
A non-native plant species is a plant that is non-indigenous and not naturally occurring to the region. (For purposes of this website, the region is eastern Massachusetts with an emphasis on the coastal environments.) When non-native species enter into an ecosystem, they have the potential to disrupt the natural balance, reduce biodiversity, degrade habitats, alter native genetic diversity, and transmit exotic diseases to native species. However, not all non-native plants are invasive. Non-native plants that are not considered invasive are those that generally do not rapidly disperse, become established, or create self-sustaining or dominant populations that would be disruptive to the natural ecosystem. CZM recommends the use of natives wherever possible but has included certain non-native species in this website that have specific coastal landscaping advantages and no known environmental impacts. Be sure to check the most recent sources of Invasive Species information.
Rosa Rugosa
Rugosa rose (Rosa rugosa) is considered to be non-native (native to eastern Asia) and potentially invasive in some regions or habitats of Massachusetts and may displace desirable vegetation if not properly managed. The shrub is often planted on coastal sites because it is extremely tolerant of sea spray and storms, making it well adapted to the coastal environment. On dune sites, the shrub is useful for erosion control and stabilization and because of its thorny stems can also be strategically planted to direct pedestrians away from or between sand dunes. However, because of its ability to spread by seeds and by rhizomes, it has an ability to outcompete and displace other native beach and dune plants. In addition, on bank sites, rugosa rose is less effective at controlling erosion and may in fact worsen the problem when other more effective erosion control plants are unable to grow due to shading effects. Therefore, care should be taken when considering planting rugosa rose on coastal properties.