Citation: Viotti, C.; Albrecht, K.; Amaducci, S.; Bardos, P.; Bertheau, C.; Blaudez, D.; Bothe, L.; Cazaux, D.; Ferrarini, A.; Govilas, J.; et al. Nettle, a Long-Known Fiber Plant with New Perspectives. Materials 2022, 15, 4288. https://doi.org/10.3390/ ma15124288 Academic Editors: Miha Humar, Christian Brischke and Ilze Irbe Received: 2 May 2022 Accepted: 13 June 2022 Published: 17 June 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). materials Review Nettle, a Long-Known Fiber Plant with New Perspectives Chloé Viotti 1 , Katharina Albrecht 2 , Stefano Amaducci 3 , Paul Bardos 4 , Coralie Bertheau 1 , Damien Blaudez 5 , Lea Bothe 2 , David Cazaux 6 , Andrea Ferrarini 3 , Jason Govilas 7 , Hans-Jörg Gusovius 8 , Thomas Jeannin 7 , Carsten Lühr 8 , Jörg Müssig 2 , Marcello Pilla 3 , Vincent Placet 7 , Markus Puschenreiter 9 , Alice Tognacchini 9 , Loïc Yung 5 and Michel Chalot 1,10, * 1 UMR Chrono-Environnement, CNRS 6249, Université Bourgogne Franche-Comté, 25000 Besançon, France; chloe.viotti@univ-fcomte.fr (C.V.); coralie.bertheau-rossel@univ-fcomte.fr (C.B.) 2 The Biological Materials Group, Department of Biomimetics, HSB—City University of Applied Sciences Bremen, Neustadtswall 30, 28199 Bremen, Germany; kathaalbrecht@web.de (K.A.); lea.bothe@hs-bremen.de (L.B.); jmuessig@bionik.hs-bremen.de (J.M.) 3 Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; stefano.amaducci@unicatt.it (S.A.); andrea.ferrarini@unicatt.it (A.F.); marcello.pilla@unicatt.it (M.P.) 4 r3 Environmental Technology Ltd., Earley Gate, Reading RG6 6AT, UK; paul@r3environmental.co.uk 5 LIEC, CNRS, Université de Lorraine, 54000 Nancy, France; damien.blaudez@univ-lorraine.fr (D.B.); loic.yung@univ-lorraine.fr (L.Y.) 6 Inovyn, 39500 Tavaux, France; david.cazaux@inovyn.com 7 Department of Applied Mechanics, FEMTO-ST Institute, Université Bourgogne Franche-Comté, 25000 Besançon, France; jason.govilas@femto-st.fr (J.G.); thomas.jeannin@femto-st.fr (T.J.); vincent.placet@univ-fcomte.fr (V.P.) 8 Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Max-Eyth-Allee 100, 14469 Potsdam, Germany; hjgusovius@atb-potsdam.de (H.-J.G.); cluehr@atb-potsdam.de (C.L.) 9 Institute of Soil Research, University of Natural Resources and Life Sciences Vienna, 1180 Vienna, Austria; markus.puschenreiter@boku.ac.at (M.P.); alice.tognacchini@boku.ac.at (A.T.) 10 Faculté des Sciences et Technologies, Université de Lorraine, 54000 Nancy, France * Correspondence: michel.chalot@univ-fcomte.fr Abstract: The stinging nettle Urtica dioica L. is a perennial crop with low fertilizer and pesticide requirements, well adapted to a wide range of environmental conditions. It has been successfully grown in most European climatic zones while also promoting local flora and fauna diversity. The cultivation of nettle could help meet the strong increase in demand for raw materials based on plant fibers as a substitute for artificial fibers in sectors as diverse as the textile and automotive industries. In the present review, we present a historical perspective of selection, harvest, and fiber processing features where the state of the art of nettle varietal selection is detailed. A synthesis of the general knowledge about its biology, adaptability, and genetics constituents, highlighting gaps in our current knowledge on interactions with other organisms, is provided. We further addressed cultivation and processing features, putting a special emphasis on harvesting systems and fiber extraction processes to improve fiber yield and quality. Various uses in industrial processes and notably for the restoration of marginal lands and avenues of future research on this high-value multi-use plant for the global fiber market are described. Keywords: Urtica dioica L.; stinging nettle; phylogeny; cultivation; fiber production and processing; phytomanagement 1. Introduction Urtica dioica L. is named “the great stinging nettle” but is known colloquially and in literature only as “stinging nettle” [1–4]. The stinging nettle Urtica dioica L., with the small nettle Urtica urens, represent the most common species of the genus Urtica, which comprises 63 species of flowering plants and belongs to the family Urticaceae (40 genera Materials 2022, 15, 4288. https://doi.org/10.3390/ma15124288 https://www.mdpi.com/journal/materials