We study the morphological evolution of secondary Widmanstätten ferrite plate by using a phase-field model for mixed-mode of growth in austenite. The model also considers anisotropy in the interfacial-energy. During the transformation, offspring-plates form at the both sides of a parent-plate by complex diffusive flow of solute carbon. The composition-dependent lengthening of parent-plate is slow as compared to the experimental observations and offspring-plate. We show that the tip of the offspring-plate shifts laterally away from the parent-plate during the transformation. The tip of the offspring-plate changes its growth-direction in order to move away from the region of accumulated solute. We also analyse the thickening behaviour of offspring and parent-plates. © 2020 Elsevier B.V.