Q: I have a tenant who refuses to pay the rent on the grounds that the yard was not maintained, but the lease agreement states that she has to maintain the yard. Can I breach the contract and give her notice of eviction?
A: The inclusion of yard maintenance in the lease agreement is a positive covenant and it can be enforced by the Landlord/lady. If she refuses to do that, it is a breach of the lease agreement and only compounds the other breach of not paying rent.
Giving notice isn't breaching the contract, so don't worry. Give her notice of 45 days to vacate and do not try to physically remove her yourself, or else you won't get any of that unpaid rent if it goes to court.