Invasions of Iris pseudacorus L. (yellow flag iris) into wetland environments can result in changes to the functioning of the ecosystem. Field-based and greenhouse studies were initiated to study the effect of water depth on regrowth rates of cut stems of yellow flag iris. The field-based experiment occurred at 41 independent populations around the perimeter of a single wetland. The greenhouse experiment was conducted to further study the effect of water depth and duration of submersion on rhizome mortality. In both studies, treatments were compared against controls. In the field-study, yellow flag iris regrowth was significantly affected by water, though there was no relationship between water depth and percent regrowth. In the greenhouse study, there was a significant positive relationship between duration of submersion and percent mortality of rhizomes. And, there was no relationship between water depth and percent mortality; indicating that as little as 5 cm of water is sufficient to kill yellow flag iris rhizomes, if the stems are cut to the base of the plant. Our results indicate a simple technique can control yellow flag iris within aquatic ecosystems without the need for chemicals or laborious hand removal.
Nomenclature: yellow flag iris, Iris pseudacorus (L.) IRPS