Question: Hi Nick, I have two questions. I have some buckthorn and oriental bittersweet on my property that I need to remove. I've been pulling the bittersweet out by hand and I bought some of the black buckthorn bags which I plan to use. Is there a certain way that these pullings/cuttings need to be disposed of?
My second question is about Canada Thistle. What's the best way to keep it under control, and are there any particular native plants that I can plant in the area to combat the thistle?
Thank you for submitting your question! In regards to the buckthorn bags we typically do not recommend these as the time that they need to sit on the buckthorn is quite long to cause death by attrition and in that time frame the bags start to degrade and the degrading plastics are difficult to collect and become pollutants. This is especially true on large scale sites, but if you have a smaller home site and you can keep an eye on them they can be effective. If you're looking for another viable option we recently provided some recommendations on how to control honeysuckle and that would directly apply to buckthorn as well. You can find that article here: https://naturalcommunities.net/blogs/news/how-can-i-control-honeysuckle-without-herbicide-use
In terms of disposal of the buckthorn and bittersweet that you removed from the site you have multiple options to ensure that it has been killed and you are not dispersing live invasives into the environment. 1) One option would be burning those in brush piles if your municipality and state allow and you have the permits to dispose of landscape waste. 2) You can chip them into very small chips and that would also kill the plants, although buckthorn has Emodin a toxic chemical to various wildlife including association with declines in amphibian diversity and abundance so you would need to be very careful with where those chips are placed and avoid aquatic and wetland areas. 3) Lastly you could dispose of it in your city brush pickup. In this case buckthorn would not cause a problem with resprouting, however oriental bittersweet has a propensity to resprout if given the correct conditions and can cause issues and further spread if not dealt with properly. To prevent this you can put the oriental bittersweet temporarily into plastic bags in warm temperatures (summer) and that will kill the live stems and prevent it from resprouting prior to you putting it into the city brush pickup. I hope one of these options work for you.
In regard to the Thistle, there are many ways to keep it under control and honestly I would need to have more context of the particular natural area you're managing to understand what native plants may help outcompete it. However, the general strategy in combating it would be the same across all communities. It would be to control parent plants, if you're able and the scale of the site allows hand pulling when it's wet is quite effective as long as it is done consistently. Always make sure that the Thistle is not flowering by cutting it to temporarily set it back and prevent it from reproducing by seed. Finally, an appropriate native plant species or seed mix put back in its place to help compete and prevent invasion in the future is key. Also remember that these activities that I just mentioned need to be conducted consistently throughout the growing season and consistently over multiple seasons to gain control in combination with planting appropriate native plants in their place. Please feel free to reach back out with details about your specific community and I can offer native plants that will compete well against Canada Thistle.
Chief Ecological Officer
Natural Communities, LLC