Because asparagus is salt resistant, gardeners have used salt to kill weeds around asparagus plants. Salt does kill weeds and other plants by pulling water out of the plant. It is also drawn into the plant when the soil is wet.Once inside the plant, it prevents the plant from moving water to other parts of the plant.utting salt on asparagus plants can damage the garden. Asparagus (Asparagus officinalis) is hardy in U.S. Department of Agriculture plant hardiness zones 3 through 8, so it is grown in much of the country.