It also invades brackish areas, ditches, and ponds with silt or clay bottoms, and shallow water in saline areas. In the North, smooth cordgrass plants have a short active period. Shoots that develop during the summer die completely in the fall and are often removed before mid-winter by ice and the tides. In the south, the growing season is longer and fall senescence is slower. Many young culms initiated in the fall live through the winter.
Fire is an important factor in the ecology of the Gulf Coast marshes.
Natural fires, caused by lighting and from spontaneous combustion in dense stands, have resulted in a fire-dependent ecosystem. Smooth cordgrass survives fire by tillering from rhizomes. Seeds may colonize bare areas following fires which leave some adult plants to produce seeds. Fires remove all aboveground vegetation. Severe fires may also kill rhizomes.