Spartina alterniflora is a spreading, rhizomatous perennial grass adapted to coastal and wetland situations. It has a deciduous foliage habit and establishes in wet, loamy soils on exposed, south‑facing sites. It requires full sun and flowers from July to September. Allow room for its rhizomes, which drive lateral spread and substrate binding.

Smooth Cordgrass (Spartina alterniflora) is a spreading, rhizomatous wetland grass for exposed south‑facing sites in the UK, flowering July to September.

Sporobolus is a nearly cosmopolitan genus of plants in the grass family. The name Sporobolus means "seed-thrower", and is derived from Ancient Greek word σπόρος (spóros), meaning "seed", and the root of βάλλειν (bállein) "to throw", referring to the dispersion of seeds.

Spartina alterniflora

Smooth cord grass | Spartina alterniflora

Spartina michauxiana is a grass that thrives in wet, marshy ground and is commonly used for wetland restoration and erosion control. It favours full sun and wet to moist clay or loam soils. Native to central and eastern Canada and most of the contiguous United States (excluding the southwest and southeast), it is also grown as an ornamental grass for damp sites. It flowers from July to September.

Prairie cordgrass Spartina michauxiana prefers full sun and wet or marshy clay and loam soils and flowers from July to September.

https://en.wikipedia.org/wiki/Sporobolus_michauxianus

Spartina michauxiana

Prairie cordgrass | Spartina michauxiana

Spartina pectinata 'Aureo-marginata' is a tall prairie cordgrass reaching about 1.8 m, suited to moist or seasonally wet ground. It prefers full sun and tolerates sandy, loamy or clay soils that remain damp. Flowering occurs from July to September, after which the seedheads can be left for winter structure.

Prairie Cordgrass 'Aureo-marginata' (Spartina pectinata 'Aureo-marginata') reaches about 1.8 m and flowers July–September, ideal for moist, sunny sites.