Abstract: This paper presents a new physics-based simulation method for flower blossom, which is based on biological observations that flower opening is usually driven by a boundary-dominant morphological transition in a curved petal. We use an elastic triangular mesh representing a flower petal and adopt in-plane expansion to induce global bending. Out-of-plane curl plays an auxiliary role in reducing the curvatures of cross-sections. We also propose to adapt semi-implicit Euler time integrator for fast simulation results, which has intrinsic damping and at least one order precision. Our system allows users to control the blossoming process by simply specifying a growth curve, which is easy to design because of the boundary-dominant property. Experimental results show that our physics-based system runs faster and generates more realistic and convincing blossom results than the existing simulation methods. Copyright 2015 John Wiley & Sons, Ltd.