A number of native plant species are common in estuarine ecosystems in New Zealand. They include:
Seagrass or eelgrass (Zostera muelleri subsp. novozelandica) is the only flowering plant in New Zealand capable of living submerged in sea water. Photo above by Bec Stanley.
New Zealand mangrove or mānawa (Avicennia marina subsp. australasica) forms intertidal forests in the estuaries of the far north.
Salt marsh areas that occur at the head of estuaries and landward of seagrass and mangrove often support sea rush (Juncus kraussii var. australiensis) and jointed rush or oioi (Apodasmia similis).
Also present in many estuaries is saltmarsh ribbonwood or makamaka (Plagianthus divaricatus).
Turf-forming plants occur where the land is drier and salt meadows often develop. The succulent glasswort (Sarcocornia quinqueflora subsp. quinqueflora) can be found in association with mats of the herb remuremu (Selliera radicans) and shore primrose or mākoako (Samolus repens).
Exotic species that occur in estuaries include cordgrass (Spartina x townsendii) which was introduced from England and planted at the Manawatū river mouth in 1913, Spartina anglica and Spartina alternatiflora (American spartina).
Mangrove (right, by John Sawyer) at Parengarenga Harbour, Northland. Glasswort (left, by John Barkla) at Pounawea, Otago