I suggest the only thing that matters is what your lease says about outdoor plants and when your lease is up for renewal , if your lease is silent then consider reporting the theft of those plants to the police and then going back to the lease if the lease is silent on the matter then add a outdoor nanny cam to record or do it from the inside and consider writing the actual owner and tell them their son needs to read the lease and then consult with their attorney to learn what part of the lease says you cant have plants outside and in the letter remind them that California is pretty darn tenant friendly when it comes to landlord tenant issues .