The Heeresgruppe Weichsel was formed in January 1945 from the Oberbefehlshaber Oberrhein Reichsführer-SS (sometimes listed as Heeresgruppe Oberrhein).

Commanders

Reichsführer-SS Heinrich Himmler (28 Jan 1945 - 20 Mar 1945)
Generaloberst Gotthard Heinrici (20 Mar 1945 - 28 Apr 1945)
General der Infanterie Kurt von Tippelskirch (28 Apr 1945 - 29 Apr 1945)
Generaloberst Kurt Student (29 Apr 1945 - 8 May 1945)

Adolf Hitler visits the HQ of Heeresgruppe Weichsel in March 1945

(Courtesy of Bundesarchiv/Wikimedia, licensed under Creative Commons Attribution ShareAlike 3.0 Germany)

Sources used

Roger James Bender & Hugh Page Taylor - Uniforms, Organization and History of the Waffen-SS, vol 2
Georg Tessin - Verbände und Truppen der deutschen Wehrmacht 1933-1945

Reference material on this unit

Hans-Georg Eismann – Under Himmler’s Command: The Personal Recollections of Oberst Hans-Georg Eismann, Operations Officer, Army Group Vistula, Eastern Front 1945
A. Stephan Hamilton - Oder Front 1945: Generaloberst Gotthard Heinrici, Heeresgruppe Weichsel and Germany's Final Defense in the East, 20 March-4 May 1945