Large quantities of salt in the soil just don’t mix well with the specimens that you’d like to grow in that soil. An excess of salt prevents them from absorbing water properly. A salty spray carried on the winds only exacerbates the problem for would-be gardeners in seaside communities. What’s the answer? You should select salt-tolerant plants for beach landscaping. The sandy soils found near beach areas retain less water and nutrients than do less porous soils, so plants growing in the former are especially susceptible to salt damage. If you’re lucky, salt damage may manifest itself only in leaf-burn; but the worst cases progress from leaf-drop to death! Thus the need for information on salt-tolerant plants, especially in Florida, a state nearly enveloped by the ocean.
Source: About.com Landscaping