To most people, an abundance of cattails indicates a healthy wetland area. As an ecologist and landscape architect, I’d like to set the record straight.
First, are cattails native?
Yes and no. The Broad Leaf Cattail is native but the Narrow Leaf and Hybrid Cattails are not. Since cattails freely hybridize and reproduce explosively, we can no longer tell what a true Broad Leaf Cattail looks like. Besides, even the Broad Leaf Cattail will dominate an area if it is left unmanaged.
With that out of the way, let me explain why cattails are called an invasive species. Cattails are the “bully on the playground”: they beat out other desirable species. I have never seen a wetland maintain diversity with a cattail component, no matter how large or small that component may be. When cattails are left unchecked in a wetland they ultimately dominate the site and crowd everything else out (with the exception of Common Reed or Reed Canary Grass, two additional extremely invasive species commonly found in degraded wetlands). Cattails thrive in disturbed areas such as a new pond in a subdivision, a roadside ditch or a remnant wetland that is not stewarded. Because cattails are such an aggressive species they must be removed from the site and managed in perpetuity. Cattails can be hand-pulled when they are small and exist in small quantities. If there are too many cattails to be hand pulled, however, they will have to be treated with an appropriate herbicide. When herbicides have to be utilized, they should be used by a licensed herbicide applicator with experience in ecology and plant identification in order to reduce the amount of site disturbance caused by the chemical application. As mentioned earlier, disturbed areas are easily taken over by weeds, including more cattails. Therefore we must take steps to fill any voids created in the plant community because of chemical treatments, otherwise Mother Nature will fill them herself. If there are desirable wetland species on-site, a stewardship crew must collect and plant the seed of desirable natives where the cattails have been killed. If you can’t collect seed, then seed should be purchased from a reputable native seed nursery and planted within the disturbed areas. Prior to planting, it is ideal to conduct a prescribed fire after the cattails are dead to expose the soil and create suitable conditions for seeding.
Earlier I mentioned a “stewardship” crew. Stewardship is the term used for maintenance of a natural area. Would you install a landscape and not maintain it? Of course not. If you are going to restore a natural area, don’t do so without a stewardship plan. Natural areas are low maintenance landscapes, not no maintenance landscapes. Stewardship is not so much about making native plants grow: it is more about making invasive species not grow. We work in stewardship under the tenet of Competitive Release. Take the Emerald Ash Borer for example. The borer is such a big problem because nothing eats it here, so nothing can control it. When it was introduced there was nothing to affect its growth, therefore it has a competitive advantage over native insects in expanding its territory. With effective stewardship, we kill the invasive plants so that the native plants have the competitive release on-site. With competitive release our native plants are given the opportunity to beat out the invasive species and destroy their ability to take hold. A stewardship process goes on forever but costs typically drop with time if done right.
Now that you know that cattails are invasive, take a look into an area invaded by cattails and notice the lack of plant and animal diversity. If cattails do not dominate the area currently, they will shortly. In the future if anyone tells you not to worry about cattails, you’ll know better… you’ll know that once the area has been cleared of cattails, it will be a beautiful, diverse and functional natural area.