Template-free photoelectrochemical deposition of semiconducting Se-Te films spontaneously produces highly ordered subwavelength scale 3D nanostructures with significant anisotropy and periodicity. The degree and direction of anisotropy can be tuned by the input polarization and feature size and pitch by the wavelength. The optical control of the resultant physical morphology is a consequence of the material self-optimizing to maximize light collection. Here we investigated the capability of the material to mimic natural phototropism exhibited by sunflowers and palm trees wherein the angle of the illumination incidence controls the direction of the structure growth out of the substrate plane. Additionally, morphological complexity could be generated by varying the polarization vector while utilizing non-normal incidence. The phototropic growth response can be dynamically directed using temporal changes in illumination; for example, zig-zag structures were produced by oscillating the illumination incidence about the surface normal while maintaining a constant polarization. The deposition was simulated using a finite-difference time domain method to model light absorption and a Monte Carlo method for mass addition and the results of the simulation successfully reproduced the experimentally observed morphologies, affirming that the phototropic response was a fully optically-induced phenomenon. The generation of these highly anisotropic light-tracking features demonstrates the ability of this technique to mimic naturally occurring phototropism to optimize the light absorption of the material.