As an on-again off-again beneficiary of the Sanctuary, Rita will be in the neighbourhood and will lend her power in helping to get rid of the vines, using fire magic to burn them away.

She'll also try using a magic detection spell to attempt to identify the magic nature of the vines, the results of which could be as vague as "yep, shit's magic" or something more specific about what they are, or who or what conjured them.