One of the most effectiveherbicide active ingredients for Japanese knotweed control is actually calledglyphosate. 

It is really effective inJapanese knotweed control because it disrupts the biochemical pathways of theplant for making plant proteins that are essential for the invasive weed tolive and grow.  The herbicide soaksthrough the Japanese knotweed leaves and is taken into the root system of theplant. 

The knotweed forms denseclumps that can grow up to three metres. It has large, ovate green leaves and astem that is hollow.  Japanese knotweedstems are similar in appearance to those of bamboo.

The greater the number ofJapanese knotweed green leaves that are showing, the more glyphosate can beabsorbed into the Japanese plant, so encouraging Japanese knotweed eradication.

Japanese knotweed controlusing herbicide can be carried out during the growing season when the plant hassome green, leafy material present.  Thecontrol with herbicide treatments takes effect usually within a few weeks butJapanese knotweed eradication can take a minimum of two sprays of Japaneseknotweed in one growing season to complete the complete eradication.

Japanese knotweed controlby this method can take up to ten days for the Japanese knotweed plant to beginto die off after the Japanese knotweed control treatment has been applied. Itis important to always watch for re-growth of Japanese knotweed though as longas every part of the plant is not dead, it may grow back up.

Another method of Japaneseknotweed control is in the removal of the ground contaminated by it. Careshould be taken with the roots when Japanese knotweed removal is in progress,more rather than less is the rule with Japanese knotweed removal of roots.  One tiny piece of Japanese knotweed canactually produce more Japanese knotweed in a very short time. 

Even with care during theJapanese knotweed removal, it is advised that a Japanese knotweed sprayingprogramme be embarked upon to fully ensure the Japanese knotweederadication.  The control of the weed isimpossible to prevent if fragments of Japanese knotweed are not sufficientlyeradicated from the contaminated ground.

It is best to leave theeradication to a competent manager perfectly trained to deal with thosesituations. And a perfect eradication would need a follow on treatment to makesure that the invasive plant does not grow back and that all the roots havebeen removed from the ground.