A method for making a dyed mulch composition or a dyed growing medium, the method comprising combining tree bark including one or more pigments and/or pigment precursors and wood components together to form an initial composition； heating the initial composition at a temperature greater than about 149° C. under steam in a pressurized vessel； processing the initial composition through a refiner with a plurality of opposing disks, the refiner separating the tree bark and wood components into fibers and separating the fibers from each other； and dyeing the wood components by the one or more pigments and/or pigment precursors while the tree bark and the wood components are being separated into fibers in the refiner to obtain dyed fibers.
