The invention relates to a method for making a plant wall including the steps of: preparing rooted trees having one or more trunks; planting the trees very close to each other; and guiding and maintaining the trees by mechanical mechanisms while they sprout in order to make them fuse together or graft onto each other, side by side, on practically the entire length of the trunks thereof so as to form, along the planting line, a juxtaposition of vertical live trunks fused to each other to form a full wall.