A Concentric Blade Trimming System with Adjustable Blades. The System includes at least one pair of rotating drums within which are rotating cutting blade assemblies. The system allows the user to load untrimmed buds continuously, and to generate an efficient, continuous flow of trimmed buds as output. The cutting blade assemblies rotate within the rotating drums independently. The cutting blade assemblies also include apparatus that will automatically adjust the blade position relative to the interior walls of the drums so that the trimming process can continue without the need to shut down for blade adjustment. In an alternate version, the blades are flexible and their adjustment is conducted manually with only a short intermission in operation of the system.