A despondent man tried to drown his sorrows Saturday — placing a funeral urn on the ground and a bouquet of red roses in his mouth before leaping naked into the Harlem River, police and witnesses said.

Witnesses in Roberto Clemente Park in the Bronx saw the man, who was carrying a large, burgundy urn, talking to himself and stripping off his clothes before his suicidal plunge into the roiling waters at 10:22 a.m.

“He was determined to take his life. Once he hit the water he started shaking. He was throwing water in his face. He was trying to hold his face under,” Christina Burtos, 30, told The Post.

Burtos and a nearby fisherman tried to extend the man a fishing rod, but he wouldn’t take it, she said.

“He was saying, ‘No, no!’ ” she said.

Another witness attempted to leap in after the jumper, but was stopped by others on shore.

“We didn’t know the state of mind of the other man. He could’ve pulled him under,” Burtos said.

The urn was etched with the name of a person who died in June, 2007.

The man’s body has not been recovered.