The highlights of Rohlf's work include his watercolors and the late water tempera sheets. Along with the watercolors by Emil Nolde, Karl Schmidt-Rottluff and August Macke, they are among the most important examples of German art of the first half of the 20th century. While the aforementioned artists often place their motifs directly on the paper wet-on-wet, Rohlfs has developed a special technique with which he superimposes the colors in an almost glazed manner.
Flower still lifes have been increasingly present in his work since 1919. This can be traced back to the artist's marriage to Helene Vogt, who has helped him with his work as a secretary since 1918. Walther Scheidig describes this connection in the following words: “One gets the impression that since the marriage, the young woman's hand in the studio has always chosen tempting flowers or fruits according to the colors and shapes that stimulated the artist. Art lovers did not ignore the magic of the flower pictures that were created at that time, and so Rohlfs finally found the economic foundation at the age of seventy-five (...). ”(Scheidig. 1965, p. 139)