Estuaries support salt-tolerant plants (halophytes) that cope with daily tides and brackish water. According to NOAA’s Estuaries Tutorial, U.S. salt marshes are zoned by elevation: smooth cordgrass (Spartina alterniflora) dominates the frequently flooded low marsh; higher marsh zones are typically covered by salt hay (Spartina patens), spike grass (Distichlis spicata), and black rush (Juncus gerardii). Extremely salty salt pannes often host glasswort.
In tropical and subtropical coasts such as southern Florida and the Gulf of Mexico, estuarine shorelines are lined with mangrove forests—including red, black, and white mangroves—instead of (or alongside) temperate salt-marsh grasses.
Source: NOAA Ocean Service — Estuarine Habitats (Estuaries Tutorial)