I recently cut down a buckthorn very near a cedar hedge. I would like to insure that it does not come back. I don’t think mechanical removal is an option. Any suggestions?
Controlling or getting rid of invasive buckthorns will require persistence, and could take a few years. Pruning them to the ground is a great first step, although stems tend to re-sprout from the stumps and as long as roots survive and spread, new plants can pop up. Buckthorns tend to establish deep roots quickly, and lateral roots can be up to 3 metres long. So a large part of the solution here is to get as much of the roots out as possible.
Common buckthorn is native to Europe and is also known as European Buckthorn. Scientific name is Rhamnus cathartica. It was introduced around the 1880s and was often used in hedgerows and windbreaks. It is shade and drought tolerant, forming dense thickets, and is listed as a noxious weed in Ontario’s Weed Control Act.
Additional strategies to get rid of or control the shrubs include:
- Pull up small plants/seedlings when the soil is wet. A good time to pull is the autumn (mid-October to mid-November), to minimize disturbance to nearby desirable plants, which should have gone dormant by then.
- Dig out larger plants, be sure to get as many roots as you can, to prevent the plants from re-sprouting. You likely won’t be able to pull out all the roots, but continued vigilance for seedlings will help control spread.
- Both male and female plants have flowers, which appear from late May to early September.Female plants produce pea-sized berries that change from green to red to dark purple as they ripen, and can be seen from July through September. As birds love the berries – and spread the seeds inside – be sure to get rid of the berries when you see them. The seeds in these berries can remain viable for 5 years.
- As with other invasive plants, the buckthorn waste (including berries) should be discarded in garbage, not composted or put in green bins.
- Finally, be careful – beware of thorns – wear heavy gloves.
In your particular situation, it seems that you have already pruned to the stump and stump removal is not possible. You can continually prune the sprouts away from the stump and after a few years with no leaves for photosynthesis, the roots may die. Painting the stump with herbicide is another solution. This is best done in the fall on a freshly cut stump. If your stump is old, it would be best to recut before applying herbicide. This link has very good information on pages 8 and 9 about chemical control – chemical to use, concentration etc:
https://winnipeg.ca/publicworks/parksOpenSpace
/NaturalistServices/Invasive/PDF/NM_Buckthorn_BMP_2014.pdf
This next link also has very good information on controlling common buckthorn. It states that you may need to apply to the Ontario Ministry of Natural Resources for a permit to use chemical control.
https://www.ontarioinvasiveplants.ca/wp-content/uploads/2016/06/OIPC_BMP_Buckthorn.pdf
In summary of this issue: A ‘natural resources’ exception exists for the use of prohibited pesticides to manage, protect, establish or restore a natural resource. This exception allows the use of prohibited herbicides for control of invasive plants on your property provided your project meets specific conditions and you obtain the necessary approvals. If your project meets the natural resources criteria specified in section 33 of Ontario Regulation 63/09 and includes the use of pesticides in accordance with Integrated Pest Management principles outlined in the BMP guide you will need to contact the Ontario Ministry of Natural Resources (www.ontario.ca) to obtain a written letter of opinion from the MNR Regional or Branch Director.