A cutter attachment for a mono-filament type trimmer implement including a trimmer support shaft and a cutter in the form of a rotatable mono-filament used for lawn trimming mounted at a free end thereof. The cutter attachment has a base secured to the trimmer support shaft above the cutter. An elongated swingable rod shaped guard has a closed guard end and a pair of free ends positioned in adjacency to the base. An attachment device joins the free ends of the guard to the base enabling the elongated swingable rod shaped guard to be swung from a "storage position" where the closed end of the guard rests on and overlies the shaft in a "guard position" where the closed guard end overlies the cutter for protecting shrubs, trees and the like. The guard is a triangularly shaped open ended rod that is secured by the attachment device to a conventional commercial type whip type weed cutter.