Jackson & Jerry
WEEDTRINE D contains diquat dibromide - though much more diluted (and expensive) in comparison to REWARD's higher concentration.
Regardless of its formulation or brand, diquat is a cell wall disrupter and has no systemic (internal plant movement) capabilities. Therefore, on rooted plants, it is incapable of moving into the plant's root system. As a result, "root kill" is often unsuccessful. But, diquat does provide very quick visual results - sometimes overnight.
One of the aquatic glyphosate products (RODEO, AQUAMASTER, GLYPRO) mentioned in other posts would likely provide much more effective root control on cattails and many other rooted plants. Treatments conducted after the catkin has begun to form are usually more effective. Visual symptom may take one to two weeks to appear. Follow the labeled directions.
Your results with diquat are typical and expected. Don't blame the product. Instead, question the source from which you purchased it for not informing you of the details regarding diquat's long-term effects on cattails - or probable lack thereof. WEEDTRINE D and REWARD are, in fact, very useful for many situations - ie. duckweed, waterhyacinth, and many other non-rooted plants. As with any "tool" - use the right one for the project.
