Coastal Gardens: Building Salt Tolerance Into Plant Choices

Coastal gardening presents a set of stresses that inland gardeners rarely contend with: salt aerosol from the ocean carried on prevailing winds, sandy soils with poor water and nutrient retention, intense wind that desiccates foliage and breaks stems, and in some areas, periodic flooding with salt.

Coastal gardening presents a set of stresses that inland gardeners rarely contend with: salt aerosol from the ocean carried on prevailing winds, sandy soils with poor water and nutrient retention, intense wind that desiccates foliage and breaks stems, and in some areas, periodic flooding with salt water. Plants that fail in these conditions fail quickly — sometimes within a single growing season.

I garden on Long Island, roughly 3 miles from Great South Bay. I get some salt spray impact, though not the intensity of a front-beach exposure. My experience is that some plants commonly sold at local garden centers are not suited to coastal conditions — rhododendrons, arborvitae, red maples — while the plants that actually look good in my neighbors' truly coastal yards are a more limited, salt-adapted group.

Per Cornell Cooperative Extension, salt damage in coastal gardens comes from two sources: airborne salt aerosol (deposits on foliage) and soil salt accumulation (from spray, flooding, or road deicing). Foliage damage and soil damage require different mitigation strategies.

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Understanding Salt Injury

Per Rutgers NJAES, salt injury in plants occurs through two mechanisms:

1. Foliage salt spray: Direct contact deposits sodium chloride on leaves. The salt draws water out of leaf cells osmotically, causing desiccation. Per Rutgers, foliage injury symptoms are brown or dead leaf margins and tips, which look similar to drought stress. Most severe on the windward side of the plant facing the ocean.

1. Soil salt accumulation: Sodium chloride in the root zone raises soil osmotic potential, reducing a plant's ability to absorb water even when soil is moist. Per Cornell Cooperative Extension, this is sometimes called "physiological drought" — the plant is surrounded by water it cannot access.

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