Cattails' slender stalks and brown seedheads are a common sight in ponds, rivers and marshes. These tall plants can quickly take over a wetland community, plus they provide a roosting habitat for blackbirds that can destroy nearby crops, according to the U.S. Fish and Wildlife Service. They can be removed mechanically by digging up their rhizomes. But herbicides are the most effective way to get rid of cattails. When using an herbicide, always thoroughly read the label.
The liquid diquat in Reward is very effective on cattails. Syngenta's Reward is a contact herbicide that will kill all plants it touches. It interferes with photosynthesis within green plant tissue, according to the Reward label. To work correctly, it must be mixed with a non-ionic aquatically registered surfactant, and it works best in clear water (avoid stirring up mud during application).
Riverdale's Aqua Neat is a liquid glyphosate formulation that effectively controls cattails. It is a broad spectrum, systemic herbicide, which is absorbed through the foliage and moves into the root system. It does not work as quickly as contact herbicides, but it works just as well. Aqua Neat requires an aquatically registered surfactant to be added for good results. Applications during extremely cool or cloudy weather will slow Aqua Neat's activity, according to the label.
Habitat's active ingredient is imazapyr, which inhibits the plant enzyme AHAS (acetohydroxyaced synthase), according to the Texas Agrilife Extension. BASF's Habitat is a systemic herbicide that does not contain heavy metals, organochlorides or phosphates, making it safe to use near humans and livestock, according to the Extension. It should not be used within 1/2 mile upstream of active potable water, according to the label. Habitat will need to be mixed with water and a surfactant to work correctly.
BASF's Clearcast has imazamox as its active ingredient. This broad-spectrum, systemic herbicide is absorbed by foliage and roots, then rapidly sent to the plants's growing joints, according to the label. Sugar beets, onions, potatoes and non-Clearfield canola should not be planted in soil irrigated with Clearcast-treated water until tests show low levels, according to the Clearcast label. To work correctly, Clearcast requires the use of a spray adjuvant.