We propose a system to generate an interactive projection mapping onto thin plants automatically. Recently, projection mapping targets have included a wide variety of objects, ranging from buildings to fish. However, it is difficult to project onto dynamic and deformable targets such as thin plants. Our system tracks dynamic and deformable plants and registers the target projection area automatically. Our system also detects and recalculates vertices in the occlusion area for the interaction, e.g., a hand touching the plant. Therefore, our system can acquire the shape of occluded area. We also propose a system in which effect animations change interactively using occlusion detection with touch event detection via a capacitive sensor. In our system, four effect animations are applied to the targets.