An attachable trimmer includes a trimming unit, an arm assembly, a limit switch, and a rod assembly as the attachable trimmer is mounted onto a mower deck of a lawn mower. The trimming unit is connected with the arm assembly while the limit switch is oppositely positioned of the trimming unit across the arm assembly. The rod assembly is connected with the arm assembly in between the trimming unit and the limit switch. The rod assembly moves the attachable trimmer in between an expanded position and a retracted position upon the user's discretion. The trimming unit is only operational when the attachable trimmer is at the expanded position as the limit switch completes an electrical circuitry to electrically power the trimming unit.