Fast Growth of Water Hemp as an Example of Reduced Weed Control

This photo is of a water hemp plant that has escaped soil-applied and post-applied herbicides.

Please note the amazing growth habit of this species. It is growing at a 1.5” per day rate in the excellent growing conditions Iowa is currently experiencing.

On Wednesday, May 28 this plant was 3” tall. At this point with a solid, multiple MOA, post application we would expect 95% control.
On Friday, May 30th, this plant was 5.75” tall. At this point, again with a solid post application, we would expect 90% control.
On Monday, June 2^nd the plant was most likely 9” tall.  At that point, control could be reduced to 60% control. As this species gets larger and more robust, we don’t simply recommend higher rates, we must realistically expect reduced control.

Todd A. Claussen; CPAg

Director of Agronomy & Technical Services