Cattails are wetland plants with a unique flowering spike, flat blade like leaves that reach heights from 3 to 10 feet. They are one of the most common plants in large marshes and on the edge of ponds. Two species are most common in US: broad leaved cattail (T. latifolia) and narrow leaf cattail (T. angustifolia).
Under the right conditions, cattails can grow and spread vigorously. The pollinated flowers develop into fluffy seed heads, blowing across a pond in autumn breezes. Just as commonly, cattails spread through their root system. The thick, white roots, called rhizomes, grow underground near the edge of ponds and in shallow swales. As long as the water is not too deep, the cattails feast off the open sunshine and abundant water, storing a large amount of food in the root system. In fact, cattails at the edge of pond can grow faster than fertilized corn in a field! The dense foliage and debris from old growth makes it very difficult for competing plant species to grow.
Cattails prefer shallow, flooded conditions and easily get established along a pond shoreline or in waters one to 1.5 feet or less in depth. When unimpeded however, the cattail beds will expand and can extend their hefty rhizomes well out into pond surface, actually floating above much deeper waters. Cattails need to have “wet feet” during most of the growing season.
Many pond owners view cattails with uncertainty because they have a tendency to grow in thick, nearly impenetrable stands, blocking the view of open water and raising the concern that they will take over and cover a pond.
Effects of Invasion
Cattail is competitively superior under stable water conditions. Maintaining open areas in semi-permanent marshes is difficult once the plant is established. The plant can occur in a variety of natural communities and form extensive monocultures rapidly through vegetative reproduction, thereby reducing plant bio-diversity. Cattail can become a problem in irrigated agricultural lands and managed aquatic systems. The plant invades farm ponds, irrigation canals, and drainage ditches which can result in impeded water flow and increased siltation.