The giant reed (Arundo donax L.) is considered one of the world’s 100 worst invasive species. The main method by which this species propagates is by growth of scattered fragments of rhizome, spreading without control with very strong, deep roots. Agricultural waste consists of lignocellulosic materials that can substitute natural wood and offer a suitable alternative with which to manufacture boards for furniture, packaging and building purposes. The objectives of this work were to obtain binderless particleboards using giant reed rhizome as the raw material, to evaluate their mechanical and physical properties according to the applicable European standards and to assess the self-binding mechanism of the particles in the board. Six types of boards (12 classes) were manufactured with giant reed rhizome biomass. They were manufactured with a temperature of 110 °C, a pressure of 2.5 MPa and pressing times of 7 and 15 min, applying one or two pressing cycles. The results achieved for modulus of rupture (14.2 N/mm2), modulus of elasticity (2052.45 N/mm2) and internal bonding strength (1.12 N/mm2) show that the mechanical properties were improved by using a smaller rhizome particle size and two pressing cycles.