A rotary mower apparatus includes a mower deck with a frame, an upper skin attached to the frame, and a lower skin removably attached to the frame below the upper skin such that a separation distance is provided between the upper and lower skins. A blade assembly is removably mounted to the deck below the lower skin and a drive is mounted to the deck and is operative to rotate the blade assembly. The lower skin can also be provided with retarding members on the underside thereof to retard the flow of cut vegetation, and to thereby cut the vegetation into smaller pieces.