Adolf Hitler is one of the most well-known and reviled figures in history. As the leader of Nazi Germany, he orchestrated both World War II and the Holocaust, events that led to the deaths of at least 40,000,000 people.
On April 30, 1945, with the war lost and Soviet troops advancing, Hitler committed suicide in his underground bunker in Berlin, shooting himself. Eva Braun, whom he had recently married, also took her own life.
According to Hitler’s wishes, their bodies were burned and then buried. His remains were exhumed in the 1970s and incinerated. The ashes were flushed into the city's sewage system. So it's mean Hitler does not have a grave, and therefore no one can bring flowers to his grave.
Although, The grave of his parents was removed a few years ago. It was used by Neo-Nazis as a place of pilgrimage, just like graves of former Nazi elites. So, yes, there are people, who want to keep those responsible for the Holocaust in good memory. They just can’t bring flowers to Hitler’s grave, but they find substitutes for that.