It is native to the coastline of southern South America, where it is a resident of salt marshes.
The inflorescence is a narrow, dense, spike-like stick of branches appressed together, the unit reaching up to 30 centimetres long.
It forms tight clumps of herbage that raise the elevation of the plants in the marsh, keeping the water from flowing in as far as it naturally would, and increasing sediment accumulation.
[3] It competes with its native relative, California cordgrass (Sporobolus foliosus), and other marsh plants such as pickleweed (Salicornia pacifica).
[3] Efforts to eradicate Sporobolus montevidensis and related hybrids in the San Francisco Bay area reduced the coverage to approximately 41 square meters in 2014, down from about 1.7 hectares (4.2 acres) in 2005.