Hi! 

Bittersweet is not on the list of the state noxious weeds, however you may want to keep the populations down on your yard before it becomes a problem in your landscape.

You may want to keep an eye on it and pull any seedlings when/if you start seeing them in early spring.  Fruit/seed production happens in the late fall so you may want to cut or mow plants to prevent seed formation. You can also spot spray the plant with a broadleaf herbicide (if there are no other desirable broadleaf plants around it).