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 dislike cattails 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.