A significant body of solo literature for the trombone has been written in the last fifty years that draws as much from the jazz tradition as from that of European classical music. While much attention has been paid to these works' use of characteristic jazz rhythms, harmonies and melodic inflections, there has been little focus on timbre, the musical element that perhaps most readily distinguishes jazz from other styles of Western music. This paper focuses on the important role jazz timbres should play in a performer's interpretation of those works that are significantly influenced by jazz. It includes explorations of the significant differences in concepts of timbre between European classical music and jazz, some of the ways in which these timbral differences are produced, and methods by which performers can develop the skills necessary to produce these varied timbres. Particular attention is paid to the importance of timbre to idiomatically appropriate performances of two significant works from the solo trombone repertoire, Robert Suderburg's Night Set (Chamber Music III) and Richard Peaslee's Arrows of Time.