The short-time rotational dynamics of colloidal silica tracer spheres in suspensions of rigid silica rods is investigated, using time-resolved phosphorescence anisotropy, as a function of tracer radius a(T), rod volume fraction phi, and the range kappa(-1) of the double-layer repulsions between the like-charged rods and tracer spheres. A large tracer size a(T) and a small screening length kappa(-1) appear to maximize hydrodynamic hindrance of tracer diffusion for given phi. The marked phi-dependence of the rotational dynamics is primarily determined by the large excluded volumes of the high-aspect ratio rods. Stokes-Einstein-Debye (SED) scaling of the rotational diffusion coefficients with the inverse viscosity of the rod suspensions holds fairly well, expect for small a(T) and large kappa(-1). The ionic strength dependence of deviations from SED scaling is rationalized in terms of an effective hard-rod model with the bare length L replaced by an effective length L+4kappa(-1). (C) 2003 American Institute of Physics.