Beat her at her own game. Keep asking her for shit. If you see her leave something in the yard, take it. Then, once she gets upset and is all like, "hey, stop mooching off of me!" then you can say, "there, see how it feels?" (you should probably have your wife standing ready at the time to play some touching, "neighbor learns a valuable lesson about life" music with a boombox when it happens). Then she'll be all like, "omg I never knew it annoyed you this much! I'm so sorry!!!!!" Then you two can have a long embrace. She'll most likely change her ways after that: give up pot, get a job, stop hanging around with a bad crowd, etcetera.

Then you knock her ass out and steal her weed. That'll show that bitch a thing or two.