Devices, guards and shields and methods for both protecting sprinkler heads and preventing unwanted vegetation from growing adjacent to the sprinkler heads, which can be applied to most if not all sprinklers on the market. The novel devices, guards and shields can be formed from a two part (upper and bottom part sections) forming a housing with ring shape housing dry and/or liquid herbicides. The ring shape can have a large center hole for allowing the ring shape to be positioned over and about the sprinkler head. The ring shaped housing includes drainage openings through the top and bottom half sections for allowing water from the sprinkler or rain water to pass therethrough and onto a replaceable herbicide which can kill unwanted vegetation such as grass, weeds, roots, trees, from growing adjacent to the sprinkler head.