Photoluminescence (PL) and optically detected magnetic resonance (ODMR) techniques are utilized to examine the effects of P implantation and post-implantation annealing on defect formation in ZnO single crystals. From ODMR, the main defects created by ion implantation include oxygen and zinc vacancies as a well as a deep donor labeled as PD. The formation of the PD defect is likely promoted by the presence of P as it could only be detected in the P-containing ZnO. The V-O and PD centers are found to exhibit low thermal stability and can be annealed out at 800 degrees C. On the other hand, a new set of defects, such as Z, T, and D* centers, is detected after annealing. Based on measured spectral dependences of the ODMR signals, the V-O, V-Zn, and PD centers are shown to participate in spin-dependent recombination processes related to red emissions, whereas the Z, T, and D* centers are involved in radiative recombination over a wide spectral range of 1.55-2.5 eV. From the PL measurements, combined effects of implantation and annealing also lead to appearance of a new PL band peaking at similar to 3.156 eV, likely due to donor-acceptor-pair recombination. The formation of the involved deep acceptor is concluded to be facilitated by the presence of P.