Native grasses that grow near the seaside have to be able to survive under conditions that might damage or kill most plants. Soils tend to be sandy and drain very quickly. Soils and water tend to be salty, and there is often more wind than in other growing environments. Because of this, these grasses need to be tough and resistant to damage. While sand, wind and salt are common to most seaside growing environments, air and water temperatures vary according to region.
The northeastern shores of the United States are generally temperate. The native grasses that grow there range from 1 foot to 12 feet in height. Tall grasses that grow near the sea include poverty dropseed (Sporobolus vaginiflorus), big bluestem (Andropogon gerardii) and switchgrass (Panicum virgatum). Heights range from 6 to 12 feet tall. Purple lovegrass (Eragrostis spectabilis), little bluestem (Schizachyrium scoparium) and saltmeadow cordgrass (Spartina patens) all grow to about 3 feet tall. Pennsylvania sedge is not actually a grass, but a grass-like plant, and grows to only 12 inches. All varieties grow inland as well and are hardy in U.S. Department of Agriculture plant hardiness zones 3 through 10.
Southeastern U.S. shores seldom see snow but sometimes may experience cold temperatures. Tall native grasses like big bluestem and switchgrass are found on both southeastern and northeastern shores, along with the less hardy sea oats (Uniola paniculata), which grow to 8 feet tall and thrives in USDA zones 7 to 11. Medium-size native grasses such as purple lovegrass, saltmeadow cordgrass and little bluestem also grow on southern shores. Coastal dropseed (Sporobolus virginicus) grows to only 8 inches tall and only in southern coastal states in USDA zones 7 through 11.
Northwestern U.S. shore areas experience few extreme temperature fluctuations. There are few extremely tall native sea grasses in this climate, but there are several of medium height. Pacific reedgrass (Calamagrostis nutkaensis) grows to 5 feet tall and is hardy in USDA zones 7 through 10, and the leafy reedgrass (Calamagrostis foliosa) is hardy in the same zones but only gets to 3 feet tall. Lyngbye's sedge (Carex lyngbyei), not a true grass with a grass-like appearance, and dunegrass (Elymus mollis) are both very hardy, growing well in USDA zones 2 through 8. They both get to about 3 feet tall. Tufted hairgrass (Deschampsia cespitosa) gets to 3 feet tall but is a little less hardy in USDA zones 4 through 9. The dune sedge (Carex pansa) is a sedge, not a grass, but is often lumped in with grasses. It gets to only 8 inches tall and is hardy in USDA zones 8 though 11.
The southwestern shores are dominated by a single state, California. The northern shores are cooler and similar to northwestern shores, but the southern shores can be quite warm and sometimes desert-like. Both dunegrass and purple needlegrass (Nasella pulchra) get to be about 3 feet tall, but purple needle grass is less hardy, growing in USDA zones 8 through 11. Foothill needlegrass (Nasella lepida) grows well in the same zone but is a little smaller at 2 feet tall. California oat grass (Danthonia california), hardy in USDA zones 8 through 10, and salt grass (Distichlis spicata), hardy in USDA zones 6 though 10, both grow to about 18 inches tall.