The landscapes and gardens on or near our coast are challenged by harsh environmental conditions. The Atlantic coast of the New York metropolitan area is known as the Coastal Plain, where there are numerous plant habitats ranging from sandy beaches with and without dunes, saltwater bays, tidal salt marshes and upland marshes. In these environments, high winds, temperature extremes, storm flooding, salt spray, glaring sun and poor salty soils wreak havoc on native ecosystems and ornamental plantings alike.
Dunes and back dunes are the most fragile ecosystems of all, subject to severe environmental conditions, and they need to be left undisturbed. Beach grass (Ammophila brevilgulata), sea rocket (Cakile edentula), beach pinwheel (Lechea maritima) and seaside goldenrod (Solidago sempervirens) work simultaneously to stabilize the ever-shifting sand. On the back dunes, hair grass (Deschmsia flexuosa), eastern red cedar (Juniperus virginiana), northern bayberry (Morella pensylvanica), switch grass (Panicum virgatum), pitch pine (Pinus rigida) and beach plum (Prunus maritima) help to establish and maintain this community.
Both the low salt marsh and the high salt marsh are dominated by the genus Spartina with salt marsh cordgrass (Spartina alterniflora) found growing where high tides flood twice daily and salt hay or salt-meadow grass (Spartina patens) growing where flooding occurs only at very high tides. Native plants of the salt marshes include groundsel bush (Baccharis halimifolia), spike grass (Distichlis spicata), marsh-elder (Iva frutescens) and sea lavender (Limonium carolinianum).
The coastal gardener's challenge is salt damage. Plants are vulnerable in several ways, such as through root absorption and salt spray on the foliage. As salt-sensitive root hairs absorb water from soil, excess salts eventually destroy their cells. While salt accumulations challenge roots, salt spray damages foliage, producing symptoms of scorching or burning. Dune plants are the most salt-tolerant. Beyond 1/8 mile from the sea, salt tolerance becomes far less of an issue.
When planting on the coast, use design solutions and maintenance techniques to create a more successful growing environment, which will also prevent the spread of invasive alien species.
Avoid disturbance of natural areas, especially dunes and native vegetation, which are critical to protecting both the natural and constructed coastal environment
Encourage and maintain naturally occurring buffer zones and stabilize with sand-binding natives as warranted
Plant salt-tolerant natives and non-invasive ornamentals wherever possible, as they are adapted to the climate and soils and have co-evolved with pollinators, wildlife and fungi
Establish windbreaks with walls, fences and hedge plantings and underplant hedges with deciduous shrubs and forbs (herbaceous plant that is not a grass, sedge or rush)
Choose plants with tough, waxy leaves and gray and/or woolly foliage
Utilize late-flowering species, as spring arrives later and autumn lasts longer
Manage any invasive exotics to prevent flowering and seed dispersal
Rinse plants occasionally during the growing season to remove salt residue and avoid the possibility of scorching
Apply two to four inches of organic mulch to reduce temperatures and conserve soil moisture
Improve sandy garden soils by incorporating organic matter
Invasive species tend to crowd out native species, disturbing and decreasing biodiversity. As gardeners, our role as responsible stewards of these changing coastal areas will help to restore balance. Below is a list of coastal tolerant plants.