Knowledgebase
taking out a non productive forsythia #869401
Asked May 21, 2024, 8:55 AM EDT
I am not able to pull out a forsythia shrub that's become too large. if i cut all branches to the ground do i have to use glyphosphate or tricopyr- meaning i cut to the ground and immediately brush the cut surfaces with one of these herbicides? Can i get away with using no herbicides. there are are 2 bushes,1.5 ft diameter "footprint" and the sit under giant oaks.
Thank you.
Oakland County Michigan
Expert Response
Hello Diane,
Apparently you have done your research. To totally eradicate the forsythia, you have two choices:
- As you suggested, cut the stems at the base of the shrub just above ground and apply glyphosate or triclopyr to the fresh cuts. This will move the herbicide to the root and eventually kill the root. https://extension.psu.edu/invasive-shrub-control
- As in the first option, cut all the above ground foliage just above the soil level. Since forsythia grows from the base of the plant through suckering, keep monitoring the root and remove any suckers as quickly as possible, This will exhaust the strength of the root and the roots and crown will eventually die. https://extension.unh.edu/blog/2020/02/when-how-do-you-prune-overgrown-forsythia#:~:text=Forsythia%20grows%20very%20quickly%20in,in%20order%20to%20maximize%20bloom.
In both cases, vigilant monitoring of suckers will be required. A well-established shrub will have significant energy in its root system and can keep sending up suckers for a long time. Without herbicide application, it may take several years to exhaust the root completely.
Hope this helps.
