Introduction
Cattails are a type of wetland plant that is a member of the Typha genus. They are perennial plants with long, blade-like leaves that can grow up to 10 feet tall. Cattails typically grow in marshes, ditches, pond edges, and other wetland areas. While they are native to North America, certain species like the non-native, invasive hybrid cattail (Typha x glauca) can quickly spread and overtake waterbodies.
Though they provide some ecological benefits, an overabundance of cattails can have many negative impacts. They can damage agriculture, infrastructure, and recreation. Cattail expansion also poses challenges for control and management. This article will provide an overview of the main negatives associated with uncontrolled cattail growth.
Agricultural Damage
Cattails can cause significant damage to agricultural crops and operations. Dense stands of cattails can reduce crop yields by competing for water, sunlight and nutrients (https://magnoliafisheries.com/cattails-good-or-bad/). Cattail roots and debris can clog irrigation systems, reducing water flow to crops. One study found that cattail biomass caused a 40% reduction in water delivery in an irrigation canal (Smith et al, 2019). Cattail stalks that break off and accumulate can also damage farm equipment like mowers and harvesters.
In rice paddies, cattail invasion has been found to reduce yields by up to 45%. The ability of cattails to thrive in moist soil makes rice fields especially vulnerable (Wang et al, 2021). Cattails also release allelopathic chemicals that inhibit the growth of rice and other crops (Chen et al, 2015).
Overall, dense cattail stands can substantially reduce the productivity of agricultural fields. Their ability to rapid spread, compete for resources, and physically interfere makes them a formidable foe for farmers.
Ecological Damage
Invasive cattails can displace native plants and alter wetland ecosystems (https://link.springer.com/article/10.1007/s13157-019-01174-7). As cattails spread, they form dense mono-culture stands that crowd out diverse native wetland vegetation like sedges, rushes, and grasses. This reduces plant biodiversity and habitat complexity. Cattails change wetland hydrology by trapping sediment and accumulating plant litter. Over time, cattails can turn diverse wetland ecosystems into cattail-dominated swamps.
These ecosystem changes negatively impact wildlife that depend on wetland habitats. For example, diverse native plants support more insect diversity, which songbirds rely on for food. Dense cattail stands also reduce open water access for waterfowl. Research shows that plant and animal diversity is much lower in cattail-invaded wetlands compared to uninvaded wetlands (https://www.usgs.gov/news/cattail-typha-invasion-north-american-wetlands). Managing cattail invasion is crucial for maintaining biodiversity and ecosystem health.
Infrastructure Damage
Cattails cause significant damage to roads, drainage systems, and foundations by clogging them up. The dense growth of cattail rhizomes and accumulation of organic sediment can obstruct drainage ditches, culverts, storm sewers and even small streams (https://archewild.com/cattail-use-in-the-landscape/). This leads to localized flooding and erosion problems. Cattails growing along roads and pavement can displace the soil and cause cracking in pavement due to root expansion (https://www.usgs.gov/news/cattail-typha-invasion-north-american-wetlands). Cattails can penetrate cracks in concrete foundations, sidewalks, and retaining walls, eventually breaking them apart. Removing established stands of cattails is difficult and expensive.
Recreational Damage
Excessive growth of cattails can limit access to waterways and block trails and scenic views, negatively impacting recreational activities. According to Magnolia Fisheries, “Excessive cattails block access to the pond and can interfere with recreational uses such as angling and boating.” Cattails growing along the edges of ponds, lakes, rivers and wetlands can form dense walls of vegetation that restrict access for recreational purposes like fishing, swimming, boating and wildlife viewing. Unmanaged growth can surround water bodies and take over shorelines as well as wetland areas, obstructing trails and blocking scenic water vistas that people enjoy.
Control Challenges
Cattails can be difficult and costly to control once established due to their resilient nature and rapid spread (https://www.wildlifedepartment.com/outdoorok/ooj/controlling-cattails-your-pond). The dense root mass forms thick underground rhizomes that can quickly populate an area. Removing the visible stalks and leaves does not kill the plant since it will regrow from the root system. Repeated cutting or burning only provides temporary control.
Cattails are also resistant to many common aquatic herbicides, so chemical control can require specialized formulations or a combination of mechanical removal and herbicide application (https://albany.cce.cornell.edu/environment/ponds/controlling-cattails). Since the plants grow in water, it is difficult to saturate the entire root zone with an effective dose. Any remaining roots will allow the cattails to recover. Complete eradication typically requires persistence over multiple seasons.
The resilient and rapid growth makes cattails labor-intensive and costly to manage. Control efforts may need to be repeated regularly to keep growth in check. Even then, periodic regrowth of cattails from surviving rhizomes is likely.
Health Hazards
Cattails can cause some health hazards, particularly allergic reactions and skin irritation in some people. The pollen from cattails can trigger hay fever, asthma, and other allergic reactions in sensitive individuals [1]. The pollen is released in large quantities by the flowers and can be spread widely by wind. People with respiratory conditions like allergies and asthma may experience worse symptoms when exposed to cattail pollen.
Direct contact with cattails can also irritate the skin in some cases. The leaves have tiny silica crystals that can cause minor cuts and scrapes. The stalks and leaves produce a gummy, sap-like substance that may cause a skin rash similar to poison ivy in sensitive people. Wearing gloves when handling cattails can prevent skin irritation.
Fire Hazards
Dense cattail stands can significantly increase fuel loads and heighten wildfire risks in some areas. As cattails die back each year, the dead plant material builds up and dries out, creating large amounts of flammable biomass. According to the USDA Forest Service, “The fuzz explodes into flames and can be used to start a fire.”
Cattail fluff is highly flammable and can allow fire to spread rapidly through wetland areas that would not normally burn. A 2016 prescribed burn conducted by the Wisconsin DNR was aimed at reducing cattail-dominated wetlands to improve waterfowl habitat and decrease fire hazards from excessive cattail growth.
Sources:
https://www.fs.usda.gov/detail/ipnf/learning/?cid=fsm9_019149
https://dnr.wisconsin.gov/newsroom/release/41381
Economic Costs
Cattails can have negative economic impacts due to the damage they cause to crops, infrastructure, and through control efforts required to manage them. Dense stands of cattails can overtake agricultural fields, reducing crop yields substantially. One study found corn yields were reduced by 50-60% in areas with just 20-40% cattail cover (https://www.usgs.gov/media/videos/importance-cattails-wetlands). Cattails also readily invade drainage ditches, irrigation canals, and other water control structures. Their rapid growth can clog these waterways, increasing maintenance costs and compromising infrastructure. For example, massive cattail growth in the Sacramento-San Joaquin Delta in California resulted in $300-500 million in annual control costs (https://pages.uoregon.edu/ecostudy/elp/ntfp/Cattails%20FINAL.htm).
Large-scale control efforts are often necessary to curb cattail spread and prevent further economic losses. Control methods like digging, dredging, herbicide application, and burning can be extremely labor and resource intensive. One federal agency spends over $2 million annually just on cattail control in the western U.S. (https://www.iisd.org/articles/press-release/media-backgrounder-beneficial-cattail-input-regional-bioeconomy). Overall, the damage and control costs imposed by cattails represent a significant economic burden in many areas.
Management Strategies
There are several methods to control the spread of cattails and restore native habitats:
Mechanical Removal – Cattails can be removed by cutting, mowing, dredging or hand-pulling. Cutting alone will not kill cattails, as they will regrow from the rhizomes. For best results, the entire root mass needs to be removed. This can be labor intensive but avoids the use of herbicides. Dredging can remove large areas of cattails but also causes major habitat disruption (https://aquaplant.tamu.edu/management-options/cattail/).
Flooding – Raising water levels above the cattails’ tolerance will cause dieback. Water levels of 1-2 feet above the soil surface for 60 days can be effective. However, this may impact other native species (https://albany.cce.cornell.edu/environment/ponds/controlling-cattails).
Herbicide Application – Aquatic formulations of glyphosate or imazapyr can be applied to cattail foliage to kill the plant. Proper timing and dosage is key to avoid impacts to wildlife and other plants. Herbicides may need to be reapplied multiple seasons for full control.
Prescribed Burning – Late spring burns can damage cattail rhizomes when food reserves are low. However, regrowth often occurs so follow-up treatment is needed. Only for large, isolated cattail stands.
Replanting Native Species – Areas where cattails have been removed can be replanted with native grasses, sedges, shrubs and aquatic plants. Selective use of mechanical removal and herbicides may facilitate native plant establishment.
