High-sodium environments can be detrimental to the growth of many plants. Plants, like all living organisms, need a little salt, but intentionally increasing the salt content can result in stunted growth and even tissue death in plants.
According to Alan Blaylock of the University of Wyoming, stunted growth is a direct result of a high-sodium environment. Sodium levels are especially hazardous to fruit-bearing plants, decreasing their ability to produce a healthy harvest.
Severe salt levels can result in death from water stress. Water stress usually occurs during a drought, when a plant is struggling for water. Salt limits the amount of water a plant can absorb, leaving a plant to die of thirst even in moist soil.
Salt outside the plant's cell walls will pull water from the cells, which makes them collapse.
Some plants can thrive in a high-sodium environment. Tamarix trees and asparagus are on the short list, but for most garden-variety plants, watering with salt is highly discouraged.
Using Salt Constructively
Salts can be used very sparingly when landscaping. Using salt on a particularly ambitious plant can help reign in the size without damaging the plant.