Hi Joanna,

Thank you for contacting the UNH Cooperative Extension Infoline with your question about how best to dispose of invasive plant material, specifically bittersweet.  The following information I hope will be helpful.

Proper Disposal of Invasive Plant Materials:

Generally, it is best to remove invasive plants before they set seed. Not only can seeds remain viable in the soil for many years, but some plants, like burning bush and multiflora rose, are spread very effectively by birds. Remember to be vigilant about checking the removal sites and pulling up the remaining seedling for the next few years.

New Hampshire regulations (Agr 3802.04) regarding the disposal of invasive plants species are as follows; "Prohibited invasive species shall only be disposed of in a manner that renders them nonliving and nonviable". Following are approved methods for rendering removed invasive plant material into 'non-living and non-viable' condition.

Home disposal Burning: Brush from removed invasive plants can be burned in a brush pile. Brush to be burned must be smaller than 5 inches in diameter. Invasive plants with easily airborne seeds should not be burned as the seeds may be dispersed by the hot air. Depending on the time of year and your town regulations, you may need a permit. Check with you local fire department for regulations and permits.

Bagging and solarizing: Solarizing is a method of heating plant material so it gets hot enough to kill all living tissue. Plant material should be put in heavy black plastic bags and left in full sun (a drive way works especially well) to dry out and heat for a few weeks or more. Alternatively, the material can be piled onto a heavy sheet of plastic or a tarp. Cover with another tarp and secure to the ground making sure that no material escapes. Again, let the pile heat through until the material is dry and dead. High enough heat will render seeds non-viable.

Composting: Do NOT compost any invasive plants unless you feel very confident that there is no viable living plant material left. Thoroughly solarized material is acceptable for composting. Closely examine the material before composting and avoid composting seeds.

Town disposal: Some towns will take brush for burning. Check with your town's transfer station.

For more information, see links below https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource000988_Rep1720.pdf https://www.agriculture.nh.gov/divisions/plant-industry/invasive-plants.htm

NH Prohibited Invasive Species https://www.invasive.org/species/list.cfm?id=53

I have also included a link to a fact sheet that discusses how best to manage bittersweet.

https://extension.psu.edu/oriental-bittersweet

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