Abstract: A trimmer height adjustment mechanism (103) having a forward guard (105a); a forward spacer (112b); and an arm (109). Such trimmer height adjustment mechanism allows a string trimmer user to: (a) achieve a uniform, user-selected cutting height for groundcover; and (b) readily engage/disengage the height adjustment mechanism so that the user can change between a uniform height setting (e.g., while cutting even terrain) and an ordinary string trimmer operation (i.e., when a user is not concerned about the height of the groundcover being cut or wishes to cut as short a height as possible, e.g., while cutting grass around the base of a tree).