A shrubland community that forms the ecotone between salt marsh and upland vegetation. Salinity levels are generally lower here than in the salt marsh (soil pore salinity ranges 7 ppt to 27 ppt) and thus technically brackish. Salt shrub areas are slightly higher in elevation than the salt marsh. Salt shrub does not usually develop on deep peat. More often, it occurs on a thin (0-10 cm) layer of peat, and soils share characteristics of both estuarine and maritime terrestrial settings. Periodic disturbance associated with storms causes die-back of shrubs.

Salt shrub is usually present as a linear feature at the upper edge of a salt marsh marking the limit of the highest spring and storm tides within a given estuarine basin. In areas where the local topography is nearly level an extensive shrubland, or brackish meadow may occur. This community is often invaded by common reed (Phragmites australis).

Salt shrub forms the ecotone between salt marsh and upland vegetation. Characteristic shrubs are groundsel-tree (Baccharis halimifolia), saltmarsh-elder (Iva frutescens), and pasture rose (Rosa carolina); salt-meadow grass (Spartina patens), black-grass (Juncus gerardii), and switchgrass (Panicum virgatum) are typical herbs. Salt shrub is almost always dominated by a stunted leading edge of Iva frutescens on the marshward side of the community. Baccharis halimifolia becomes more dominant only in the older, more developed, landward side. The landward side of salt shrub is usually the most diverse.