The term “pansy” (an effeminate man) was popularized in the 1920s by New York City-born actor, comedian, singer, vaudevillian, and pianist Jimmy Durante (1893-1980). The Durante routine “So I Ups to Him” was used at the Club Durant (probably in 1923) and in the 1929 production Show Girl.
   
Zit’s Theatrical Weekly (New York, NY) explained on March 23, 1935:
   
“Jimmie Durante’s many sayings have been adopted in daily slang…Most popular is the word ‘Pansy’ with its inference…It started while in rehearsal of his number, ‘So I Ups to Him’ with the trio and the band in vaudeville…He sought to replace “Fairy” in the song…Bill Drewes, his trombonist, suggested the name of that flower…Durante picked it up and made it popular and since then every comic and erstwhile humorist has used ‘Pansy’ at least once, and the laymen responding with a laugh carried it further till the general every day audience adopted it.”
 
“And the reader who recently wrote a tirade against us because we used the word ‘pansy’ in referring to female impersonators should be tickled to death to know the former Picardy Club was renamed last Thursday night ‘The Pansy Club.’ ... Hate it? ... They LOVE it! ... And it’s up in electrics, too, in case you’d like to know” was printed in the Brooklyn (NY) Daily Eagle on December 20, 1930. The Pansy Club was located at 204 West 48th Street and Broadway, right in Manhattan’s Times Square. The club lasted only until 1931, but it helped to create a national “pansy craze” that lasted until the 1933 death of famous drag performer Jean Malin (1908-1933). Malin performed at the Club Abbey (46th Street and 8th Avenue). Another popular club was the Club Calais (125 West 51st Street).
   
The term “pansy” is still used today, but is dated.
   
       
Wikipedia: Pansy Craze
During the Pansy Craze of 1930–1933, drag queens, known as “pansy performers”, experienced a surge in underground popularity, especially in Los Angeles, New York City, Chicago and San Francisco.
 
Performance styles
The early 1930s saw a new development within a highly commercial context, bringing the gay subculture of the enclaves of Greenwich Village and Harlem onto the mainstream stages of midtown Manhattan in a veritable Pansy Craze from 1930 until the repeal of prohibition in 1933. After the repeal of prohibition, this tolerance waned. Any sympathetic portrayal of gay characters (termed sexual perverts) was prohibited by the Motion Picture Production Code (or Hays Code) from being included in Hollywood films. Performer Ray Bourbon was arrested many times for his act, considered tame by today’s standards.

In many ways, New York City set the tone, particularly in its “bohemian artistic enclaves” of Greenwich Village and Harlem, as well as in the cabarets and speakeasies around the Broadway Theater District centered on Times Square
 
(Oxford English Dictionary)
pansy, n. and adj.
A homosexual man; an effeminate man; a weakling. Frequently derogatory.
[1922   ‘R. Werther’ Female-impersonators iii. v. 151   Three short, smooth-faced young men approached and introduced themselves as Roland Reeves, Manon Lescaut, and Prince Pansy—aliases, because few refined androgynes would be so rash as to betray their legal name in the Underworld.]
1926   Life 20 May 23   All About Sex..at the Greenwich Village Theatre… A series of sketches dealing with gentlemen hiding under beds and spectacular numbers showing the different kinds of pansies in the world’s history.
1928   in J. N. Katz Gay/Lesbian Almanac (1983) 447   All around the den, luxuriating under the little colored lights, the dark dandies were loving up their pansies.
     
Green’s Dictionary of Slang (2010) by Jonathon Green
pansy n. (also pansie)
(also pansy-wansy, panz) an effeminate and/or homosexual man [redup.; abbr.].
1917 E.E. Cummings in Dupee & Stade Sel. Letters (1972) 2 July 27: About the tent in which Brown and I sleep his nomen is ‘Pansy’.
1919 Aussie (France) XI Feb. 10/1: He had not lived in Aussie long enough to become Australianised. He had a round, rosy dial and a soft-speaking voice. We called him ‘Pansy’ from the jump.
1920 Ade Hand-made Fables 63: For every Pansy in this Conservative Town there were 14 Rutabagas.
1930 J. Lait Put on the Spot 17: Pour me a shoot—no, make it a man’s size—I ain’t no pansy.
 
“So I Ups to Him” by Jimmy Durante [Used at the Club Durant, probably in 1923. Also used in the 1929 production Show Girl.—ed.]
“Roses are red
Violets are blue
Horses neck
Do you?
A PANSY!”
(Durante meets the same person three years later. “The Pansy!” is heard near the end of the number.—ed.)
   
Wikipedia: Show Girl (1929 musical)
Show Girl is a musical by William Anthony McGuire that ran from Jul 2, 1929 to Oct 5, 1929. The show tells the story of aspiring Broadway showgirl Dixie Dugan (played by Ruby Keeler) as she is pursued by four suitors (played by Eddie Foy, Jr., Joseph Macaulay, Austin Fairman, and Frank McHugh).[1] The music was written by George Gershwin, with lyrics by Ira Gershwin and Gus Kahn.
(...)
Act Two
. An American in Paris
. Home Blues
. Broadway, My Street (Lyrics by Sidney Skolsky, music by Jimmy Durante)
. (So) I Ups to Him (Music and lyrics by Jimmy Durante)
       
Newspaeprs.com
15 November 1929, Scranton (PA) Republican, “On Broadway” by Walter Winchell, pg. 9, col. 2:
Things I Never Knew Till Now
(...)
And that the same phonograph recording company which made Jimmy Durante alter his “So I Ups To Him!” song (by changing his famous line, “He’s a fairy!” to “He’s a pansy!”), specialize in unedited songs by Bessie Smith or Ethel Waters whose ditties are the most offensive ever known.
     
Newspapers.com
20 December 1930, Brooklyn (NY) Daily Eagle, “Reverting to Type” by Rian James, pg. 9, col. 1:
And the reader who recently wrote a tirade against us because we used the word “pansy” in referring to female impersonators should be tickled to death to know the former Picardy Club was renamed last Thursday night “The Pansy Club.” ... Hate it? ... They LOVE it! ... And it’s up in electrics, too, in case you’d like to know.
   
Newspapers.com
29 January 1931, Daily News (New York, NY), pg. 3, col. 4:
Whoops, Dearie!
Mean Old Police
Raid Pansy Row
By TOM CASSIDY.
(...)
The places visited at 1 a.m. were the Pansy Club, 204 West 48th st., where Karyl Norman, the Creole Fashion Plate falsettos, and the Club Calais, 125 West 51st st., where Jackie May leads a bevy of whoops sisters.
 
Decision to launch a crusade against spots offering such entertainment was decided on, it was said, following the Schultz shoot-
Newspapers.com
(Pg. 37, col. 1—ed.)
WHOOPS, DEARIE! MEAN OLD
POLICE RAID PANSY LANE
ing at the Club Abbey, where Jean Malin began the vogue for effeminate entertainment with his ditty: “I’d rather be Spanish than mannish.”
 
In both places visited arrests were made only for liquor possession and the lavender lyric singers and their satellites were undisturbed.
 
Newspapers.com
22 October 1931, Daily News (New York, NY), “Behind the News” by Sidney Skolsky, pg. 44, col. 1:
Jimmy Durante could be Cyrano de Bergerac if Cyrano’s nose was a little longer and he didn’t use such flowery language.
 
Cyrano would have to learn to say: “So I ups to him. And after two years—the pansy!”
 
Newspapers.com
19 February 1934, Daily News (New York, NY), “Mainly About Manhattan” by John Chapman, pg. 34, col. 3:
Some bits of hobo slang come in from William J. Walsh.
(...)
Fruit—a pansy.
 
23 March 1935, Zit’s Theatrical Weekly (New York, NY), “Vaudeville Philosophy” by Speakin’ Frank, pg. 3, col. 3:
As long as I can remember people have been howling “I saw it first.” Long before Columbus had a tough time proving it, the question had had its juggling from time to time. Miners all over the world are battling over it.
We find that a daily conjecture in show business. Say, even the columnists are adding the “don’t forget you saw it here first” line. But amongst the show people we have heard the indignant rise of the voice to emphasize that they had heard it, said, saw or did it first…well, many times it has been proven true.  But you can usually bank upon the originality of a good many gags, bits, or even daily idioms if you peer into the vaudeville game where much of our present words and slang phrases first burst into dawn by a casual conversation amongst the troupers. Observations would show that troupers live in a world all their own, fitting and exchanging their hobbies, ideas, and habits amongst themselves. Instinctively they seek to originate something, to be a little different, and their language has even found a different aspect than the layman and often we will hear a slang word, or an idiom passed on to the world at large where it gets its relay to farther usage. One may classify the troupers as a tribe of different people. The laymen are always curious about the lives of the troupers and often are eager to catch on to a new saying or gag that may circulate amongst the actors or those associated with them…Many coined idioms originated from the chatter backstage within the social habitat…
(...)
...Jimmie Durante’s many sayings have been adopted in daily slang…Most popular is the word “Pansy” with its inference…It started while in rehearsal of his number, “So I Ups to Him” with the trio and the band in vaudeville…He sought to replace “Fairy” in the song…Bill Drewes, his trombonist, suggested the name of that flower…Durante picked it up and made it popular and since then every comic and erstwhile humorist has used “Pansy” at least once, and the laymen responding with a laugh carried it further till the general every day audience adopted it…
 
The Bowery Boys   
Welcome to The Pansy Club: leave your wig at the door
By Bowery Boys
June 18, 2010
(...)
LOCATION: The Pansy Club Times Square, 48th Street and Broadway, Manhattan
In operation December 1930-31
(...)
A gang shooting closed Club Abbey in January, and the police raided the Pansy Club that same month.