An Etymological Dictionary of the German Language/Annotated/Riet
Riet (in the Low German form Nied), neuter, ‘reed,’ from the equivalent Middle High German riet, Old High German riot, earlier hriot, neuter; common to West Teutonic in the same sense; compare Old Saxon hreod, Dutch riet, Anglo-Saxon hreód, English reed. Gothic *hriuda is wanting. Pre-Teutonic *kreudho- is not found in the other groups.