An automatic machine (10) for herbaceous grafting which comprises a base (11) supporting at least a device (20) suitable for supporting a rootstock of a plant (P) to be grafted, comprising a support member (27) defining a substantially cylindrical concave portion suitable for receiving a stem of a plant (P) to be grafted and cutting means comprising a blade (L1) suitable for cutting the stem of the plant (P) and actuated in translation by actuating means, characterised in that the blade (L1) is actuated by the actuating means (35), with a translation motion having at least a component that is parallel to the axis of the concave portion (27).