Am I the Asshole for Being Pissed at My Flatmate for Taking Plant Cuttings Without Asking?

A new girl recently moved into our flat within one month of her moving in. I had noticed that some of my plants looked like someone had taken a cutting. The new girl admitted to it, but to ask next time fast forward three weeks and more cuttings are missing. Am I the asshole for being angry about this? My partner thinks I should just let this go. Confront her. I would give her an eviction letter. This would make me go crazy.