Every HOA I've dealt with has the lawn under the responsability of the home owner, even the lawn in between the sidewalk and the curb most times. They will bitch to no end if your lawn is not satisfactory as well.

Or you could spray some random oily substance on her garage door and alert the local religious freaks by telling them you spotted the virgin mary on your neighbor's door. Everyone would be trampling all over her lawn....lol.