Phalaris arundinacea is a Eurasian cool-season grass that has colonized wetland margins, stream banks, and disturbed wet areas across North America with the aggressive efficiency that makes it a serious ecological threat. Spreading by both rhizomes and seed, it forms dense, tall stands that can reach 6 to 9 feet and persist through winter as collapsed, matted debris offering little to wildlife. Once established it is extraordinarily difficult to eradicate, with a deep root system that allows it to persist through drought as well as flooding.

It tolerates virtually any soil type, a wide pH range, and conditions from full sun to part shade. The NC Invasive Plant Council lists it as invasive, as do authorities in many other states. Ornamental variegated cultivars such as Phalaris arundinacea var. picta are sometimes sold as garden plants under the name ribbon grass or gardener's garters, but they too can revert to the invasive green type. Any planting near water or disturbed ground carries real risk of establishing a persistent and damaging colony; native alternatives such as Carex, Juncus, or Schizachyrium deserve consideration in its place.