The flower head of the parent plant can produce 250,000 seeds, which are then wind-dispersed. Seeds remain viable in the seed bank for up to 100 years. Cattail seeds prefer freshwater, and will not germinate unless saturated in at least 0.5-1 inch of water. Cattails also reproduce asexually by rhizomes. During the first summer of vegetative propagation, rhizomes grow about two feet in length.
New shoots emerge at the rhizome around mid-summer.
Cattails can quickly dominate a wetland plant community and produce monotypic stands that reduce the overall habitat value. The acreage of cattail-dominated wetlands in the United States has increased drastically since the early twentieth century due to changes in hydrology and land use. The optimal control technique for a given site will depend on the hydrologic state of the site, the size of the area to be managed, and if the manager is able to manipulate water levels. The control of cattails by the manipulation of water level must be timed to the annual cycle of carbohydrate storage. Special leaf and stem cells called aerenchyma provide air passage from both living and dead leaves to the rhizomes.