Plants That Don't Mind Brackish Water

Grasses

• Cordgrasses (Spartina spp.) form dense colonies in water or along the water's edge. Salt hay cordgrass grows to about 1 to 2 feet tall, Townsend's cordgrass (Spartina x townsendii) gets to about 4 feet tall and is sterile, and smooth cordgrass (Spartina alterniflora) reaches 6 to 7 feet. All grow well in U.S. Department of Agriculture plant hardiness zones 4 through 10, but some may be considered invasive so check local laws before planting. Seagrass or eelgrass (Zostera marina) bears dark green ribbon-like leaves and is usually submerged, often below the low tide mark where the water is cooler. It's found in seaside areas as far north as Alaska and as far south as North Carolina, where the USDA zones range from 1 to 9. Sea oats (Uniola paniculata), hardy in USDA zones 6 though 10, grows along the water's edge and bears attractive nodding seedheads.

Flowering Plants

• A number of attractive flowering plants tolerate brackish water and grow along the water's edge. Purple loosestrife (Lythrum salicaria), hardy in USDA zones 3 through 9, bears pretty purple flowers on tall spikes; however it may be invasive in some states so check state laws before planting. Sea lavender (Limonium nashii) bears clusters of purple flowers and is hardy in USDA zones 5 through 9. Saltcedar (Tamarix ramosissima) is a large shrub or small tree, and forms small dusty pink flowers at the ends of its branches. It is highly tolerant of a number of harsh environments, including proximity to brackish water, but it may be considered invasive in some states. It is hardy in USDA zones 3 through 10, and its invasive tendencies become more prominent in zones 8 through 10.

Shrubs and Trees

• Ribbonwood (Plagianthus divaricatus) is a shrub native to New Zealand and has gray-green foliage and is hardy in USDA zones 8 through 10. It's often found on salt marsh islands or along the water's edge. Saltbush (Atriplex canescens) also bears gray-green foliage. It's hardy in USDA zones 3 through 10 and may be found along the water's edge. A number of trees labeled as "mangrove" share the common characteristic of having aerial roots that grow directly in the water. Red mangrove (Rhizophora mangle), black mangrove (Avicennia germinans) and white mangrove (Laguncularia racemosa) all grow in brackish marshy areas in Florida and along the Gulf Coast and all are hardy in USDA zones 10 and 11.

Ferns

• Ferns may seem delicate, but some are tough enough to resist the damage brackish waters may inflict on more sensitive plants. Java fern (Microsorum pteropus), hardy in USDA zones 9 through 11, produces undivided fronds and grows along the water's edge but can also live well if submerged. It grows to only about 1 foot tall. Mangrove ferns (Acrostichum spp.), hardy in USDA zones 9 through 11, are also known as leatherferns and get to about 6 feet tall. The foliage is shiny and leathery.