[4] In 1958 he won second prize at the ARD International Music Competition in Munich together with his elder sister, the Mannheim pianist Ursula Trede-Boettcher.

[7] In 1990, he was the soloist in the world premiere of Giselher Klebe's Cello Concerto which was composed for him, with the Philharmonic conducted by Daniel Barenboim.

[5][4] Composers such as Henri Dutilleux, György Ligeti, and Witold Lutoslawski appreciated his interpretation of their works.

[6] He became a member of the Bayerische Akademie der Schönen Künste in 1988,[10] and was chairman of the jury of the Grand Prix Emanuel Feuermann cello competition.

[4] Together with his two sisters, pianist Ursula and violinist Marianne, Boettcher formed a piano trio that continued to give concerts even in his old age.