Introduction to Cattails
Cattails, also known as reeds or bulrushes, are tall wetland plants that grow abundantly throughout North America. Though often considered a nuisance weed, cattails are ecologically and economically important plants that provide food and habitat for wildlife.
The two most common cattail species in North America are the native common cattail (Typha latifolia) and the invasive narrow leaf cattail (Typha angustifolia). Cattails typically grow in shallow, slow-moving freshwater wetlands like marshes, swamps, ditches, and the edges of ponds and lakes. They thrive in sunny locations with muddy, nutrient-rich soil.
As aquatic plants, cattails play an important role in wetland ecosystems. Their dense root systems help prevent erosion and filter contaminants from water. Cattails provide shelter and nesting sites for birds and habitat for fish and other wildlife. They produce an abundance of seeds and shoots that are eaten by various animals.
Cattails spread aggressively through underground rhizomes and abundant wind-dispersed seeds. They readily colonize disturbed wetland areas and can form dense monoculture stands that crowd out other plant species over time. Periodic fires, floods, grazing, and other disturbances help keep cattail growth in check.
Though cattails have ecological benefits, aggressive growth can clog waterways and drainage areas. Thick cattail stands also reduce biodiversity and access for wildlife. Controlling cattail overgrowth is often necessary, but should be balanced with conserving their important ecosystem functions.
Benefits of Cattails
Cattails provide many benefits in aquatic ecosystems. One of the most well-known uses of cattails is as a food source. The rootstock, shoots, and flower spikes of cattails are all edible and rich in starch. Native American tribes traditionally ate cattail roots and shoots as vegetables. The pollen from cattail flowers can also be used as a flour substitute in baking. In survival situations, cattails provide an abundant and nutritious food source (https://www.mtpr.org/arts-culture/2018-04-02/cattail-plant-of-a-thousand-uses).
Cattail stands also provide important habitat for wildlife. The dense growth offers shelter and nesting sites for birds like red-winged blackbirds, marsh wrens, and ducks. Mammals like muskrats and beavers use cattails to construct lodges. The cattail flowers produce large amounts of nectar, providing food for pollinators. Decomposing cattail litter contributes nutrients and biomass to the aquatic ecosystem (https://magnoliafisheries.com/cattails-good-or-bad/).
The extensive root system of cattails helps control erosion along shorelines. The roots bind soil together, preventing it from washing away. Cattail stands also slow water flow, allowing soil particles to settle out. Their presence helps stabilize pond and lake banks, reducing turbidity.
Cattails are very effective at removing contaminants from water through rhizofiltration. As water passes through the dense root mat, pollutants like excess nutrients, heavy metals, and organic chemicals are absorbed and broken down. Cattail stands provide a natural filtration system to improve water quality (https://www.lybrate.com/topic/benefits-of-cattail-and-its-side-effects).
When Cattail Growth Becomes a Problem
While cattails play an important ecological role, they can become problematic when their spread is left unchecked. Dense stands of cattails can aggressively invade wetlands and waterways, posing issues in certain situations:
Cattails spread through underground rhizome growth and seed dispersal. Under ideal conditions, they can form into monocultures that crowd out other beneficial native plants. This reduces biodiversity and habitat quality.
Thick cattail stands obstruct waterways used for boating, fishing, and other recreation. As dead plant matter accumulates, drainage can be impaired and flooding exacerbated.
Cattails block views and access to open water. Their visual impact can reduce shoreline property values and aesthetics.
Decaying cattail litter diminishes water quality by releasing phosphorus and nitrogen into the water. This can lead to algal blooms and eutrophication.
When cattail growth significantly impedes usage or ecological function, management intervention may become necessary. However, impacts should be carefully weighed before altering natural wetland communities.
Manual Removal Methods
Manually removing cattails requires physically pulling the plants and excavating the tubers under the sediment. This labor-intensive process is most effective for spot treatment of small areas.
Cutting the leaves and stems above the waterline will remove the visible part of the cattail, but regrowth can occur from any remaining tubers. For more lasting control, the tubers and rhizomes must also be removed. This can be done by digging under the plant with a shovel or rake to extract as much of the root mass as possible (https://blog.pondking.com/cattail-control-in-ponds). Any small tuber fragments left behind may allow the cattail to regrow.
For large infestations, cutting the stems first can make digging out the tubers easier. The shoots can be cut using a scythe, machete, or weed trimmer. Hand removal will likely need to be repeated several times per year to control regrowth. Raking the area can help loosen and remove additional tubers.
The manual effort required makes this method most practical for small areas of growth. Removing cattails by hand may be preferable near environmentally sensitive areas, but takes persistence and continued maintenance (https://www.firesafecouncil.org/controlling-cattails-without-harming-wildlife-effective-strategies-for-removal/).
Herbicide Treatment
Herbicides containing glyphosate or imazapyr can be effective at killing cattails. Glyphosate is a non-selective herbicide that is absorbed through the leaves and translocated to the roots, killing the entire plant. Imazapyr is also a systemic herbicide that is selectively absorbed by plants in the aster family, like cattails. For best results, herbicides should be applied in late summer or early fall when cattails are actively growing and translocating nutrients to their rhizomes. This timing allows the herbicide to travel to the roots and prevent regrowth. According to Pond Boss Forum, a glyphosate herbicide called CattPlex with an added surfactant was effective at killing cattails when applied at this time.
Proper application technique is also important for good cattail control. The herbicide should be applied via spraying or wiping directly onto the leaves, using care not to get herbicide into the open water. Follow all label instructions for correct dilution rates and safe application. It may take several herbicide applications over multiple seasons to fully eradicate an established stand of cattails.
Biological Control
One potential method for reducing cattail growth is through biological controls such as grazing animals or insects. According to How to Control Cattail – AquaPlant: Management of Pond Plants, there are no readily available biological control options for cattails at this time.
Some studies have looked at using muskrats and geese that eat cattail shoots and rhizomes as a form of biological control. However, relying on grazing animals alone is often not effective enough to control large cattail stands. Insects like certain beetles and moths can also feed on cattails to a limited extent. Research is ongoing into fungal pathogens that may help control cattails in the future, but currently there are no approved biocontrol agents available.
While biological controls like grazing animals and insects can put some pressure on cattails, they rarely fully remove cattail stands. Their impacts are often temporary and localized. More research is needed to develop biological control methods that can provide effective long-term management of invasive cattails in ponds and other wetland areas.
Altering Growing Conditions
One of the most effective ways to control cattail growth is by altering the growing conditions that allow them to thrive. Cattails prefer shallow, flooded conditions with freshwater and disturbed, nutrient-rich soil. By changing these ideal conditions, you can reduce cattail survival and regrowth.
Lowering water levels is a common technique for slowing cattail spread. Cattails thrive in 0-2 feet of standing water. Lowering water levels to at least 12 inches below the soil surface during the active growing season in summer and fall exposes the roots to desiccation and increases vulnerability to control methods like mowing or herbicide application (see Managing cattails with water level control). The roots must stay dry for an extended period to damage the rhizomes and limit regrowth. This technique is most effective when you have control over water level management in a wetland or pond.
Increasing salinity of the water can also deter cattail growth. Cattails prefer freshwater and are not tolerant of high salt levels. Introducing brackish water or increasing salinity can stunt growth by altering the ideal growing conditions (see Management and Control of Cattails). However, changing water chemistry substantially may negatively impact other flora and fauna, so ecological impacts should be carefully considered.
Soil disturbance through dredging, raking, or cultivating bottom sediments can reduce survival of existing plants. However, disturbance also generates favorable conditions for new seeds to germinate, so additional control methods are required to limit regrowth.
Preventing Regrowth
Repeated management, monitoring, and maintenance are often necessary to prevent cattails from regrowing after removal. According to Cornell Cooperative Extension, cutting or pulling cattails must be repeated several times per year to keep roots from resprouting. They recommend checking for regrowth at least monthly during the growing season. Similarly, The Pond Guy notes that herbicide treatments may require multiple applications over 2-3 years to fully eradicate cattail roots. After the initial knockdown of growth, diligent monitoring is needed to spot and remove any new sprouts before they can spread. Maintenance may include hand pulling small regrowth or carefully targeted herbicide spot treatments. Consistent long-term management is often the key to successful prevention of regrowth after cattail removal.
Considering Ecological Impacts
When considering removing cattails from a wetland area, it’s important to first evaluate the potential ecological impacts. Cattails provide food and habitat for many wildlife species, so removing them could negatively affect biodiversity. For example, the seeds are eaten by ducks, geese, swans, red-winged blackbirds, marsh wrens, and other species. The stalks provide nesting material, and the dense growth offers cover from predators.
Cattails may also provide habitat for rare or endangered species in some wetlands. For instance, certain butterflies and moths depend on cattails at some stage of their lifecycle. Wetlands with diverse native vegetation tend to support more species compared to cattail monocultures. However, completely removing cattails can open a wetland up to invasive species as well.
In general, retention of native cattail stands is preferable for maintaining wetland ecosystem health. Cattails help filter pollutants and prevent erosion. They also sequester carbon and regulate water levels. If cattail growth must be controlled, it’s advisable to do so selectively and in moderation. This will help preserve portions of the wetland habitat while managing specific problem areas.
Before undertaking any large-scale cattail removal, consult with local wildlife agencies to understand potential impacts on sensitive species. Look for opportunities to enhance wetland plant diversity when controlling cattails. With some ecological awareness, cattail growth can be managed in a sustainable way.
Sources:
Controlling Cattails – Cornell Cooperative Extension
The Quandary Over Cattails – City of Sanibel
When to Leave Cattails Intact
While cattails can become invasive in some cases, they also provide important benefits that should be carefully considered before removal. Cattails help stabilize pond banks, prevent erosion, filter contaminants from water, and provide habitat for wildlife.
According to Cornell Cooperative Extension’s guide on Controlling Cattails, these plants “help protect the banks of a pond from erosion. They intercept and reduce the force of small waves and wind on the shore.”[1] Their extensive root systems hold soil in place.
Cattails also absorb excess nutrients like nitrogen and phosphorus from water, acting as a natural filtration system. Their presence can improve water quality.[2]
In addition, cattail stands provide vital nesting sites, food sources, and shelter for birds, insects, and other wildlife. Removing all the cattails in an area can negatively impact local ecosystems.
Before taking action to eliminate cattails, carefully assess if overgrowth is actually causing significant problems that warrant control measures. In many cases, the ecosystem benefits of preserving some cattail stands may outweigh the desire for removal.
