'Aspidistra' was the Allied final operation in which personnel of the Office of Strategic Services' Morale Operations branch took part, in co-operation with the Special Operation Executive’s Political Warfare Executive (January/May 1945).

The undertaking was the 'ghost voicing' of German radio broadcasts. The project involved using the 600-kW Aspidistra transmitter at Woburn, England, literally to overpower radio signals and break into German broadcasts with anti-Nazi slogans, satirical comments, or sarcastic replies. Such an operation was carried out on 27 January 1945 when the Königsberg home service was interrupted and a speech by Hans Fritzsche, the director of the German propaganda ministry’s radio department, was heckled. Later, between 24 and 25 March and again on 30 March, 'Aspidistra' broke into broadcasts heard in Köln, Berlin, Frankfurt and Hamburg. During the Frankfurt broadcast the ghost voice announced the approach of a fictitious Allied tank force, ordered mobilisation of Red Cross and women’s auxiliary groups in areas surrounding Frankfurt, and ordered police, Volkssturm, and other security personnel to detain the occupants of a grey car containing four uniformed impostors near the city.

Goebbels recorded the operations in his diary, noting that the Americans were 'trying to play the same game with the German people as we played with the French during our western offensive in the summer of 1940.' The Germans quickly denounced the interruptions but could not jam the airwaves without ending their own programmes carried on the same frequencies. They therefore found themselves at the mercy of Allied propagandists, uncertain as to when and where the next intruder operation would take place. It was admitted by one official that 'considerable misunderstandings and great unrest were caused among the population by the intrusion of enemy wireless announcements on the German wireless.'

The success of the operations convinced Major General Robert A. McClure, the chief of Psychological Warfare Division at the Supreme Headquarters Allied Expeditionary Forces, that they had 'caused the enemy considerable anxiety which should be exploited to the full'. The broadcasts continued until April 1945.

As with others of the Morale Operations branch’s covert activities, 'black' radio operations ended late in April and early in May 1945, just before the final defeat of Germany. The Political Warfare Executive informed the Office of Strategic Services that all operations would come to an end on 1 May. It is difficult to assess the effectiveness of the Morale Operations branch’s efforts with any degree of real accuracy. The relatively small scale of the branch’s activities, in comparison with propaganda campaigns carried out by the US Army and the US Office of War Information and with the Allies' conventional warfare efforts, seems insignificant. Unlike the US Army, the Morale Operations branch lacked the personnel to conduct major post-war studies, and few surveys were completed describing the number of Germans who were exposed to or influenced by the Morale Operations branch’s work.

Perhaps the best indication of success is found in the official Office of Strategic Services history, which reported that the Morale Operations branch continued its efforts despite great handicaps at home and abroad and that by the war’s end Allied military and political agencies had accepted the principle of morale operations. Most significantly, the branch had brought to the attention of the US authorities a weapon which the USA had not systematically and effectively employed up to this period. It drew attention to the advantages of a specialised type of intelligence information on the morale, social divisions and underlying worries of foreign peoples, and how these could be used for national advantage. The Morale Operations branch eventually became just the type of organisation that Edmond Taylor and William Donovan had envisaged in 1941, and it clearly succeeded in its mission of fighting fire with fire, attaining a degree of sophistication never before imagined.