Herbivores, not herbicides, may be the most effective way to combat the spread of one of the most invasive plants now threatening East Coast salt marshes, a new Duke University-led study finds. Phragmites australis, or the common reed, is a rapid colonizer that has overrun many coastal wetlands from New England to the Southeast. A non-native perennial, it can form dense stands of grass up to 10 feet high that block valuable shoreline views of the water, kill off native grasses, and alter marsh function.