In this paper, a mathematical model is proposed for analytical study of plant growth subjected to the effect of toxic metal. The associated state variables are plant biomass, concentration of nutrients and concentration of toxic metal in the soil. The assumption is that the toxic metals present in the soil interferes with nutrient availability and hence, adversely affect the plant's growth. This effect is studied by introducing the time-lag (delay) in consumption and utilisation coefficient due to less availability of nutrients in the presence of toxic metal. The inclusion of delay disturbed the stability of the interior equilibrium of the system and Hopf bifurcation occurred at the critical value of delay parameter. Further, the direction, stability and period of these bifurcating periodic solutions are also studied as well as sensitivity analysis of state variables with respect to model parameters. Numerical simulation support analytical results using MATLAB.