No, it wasn’t Arlene Francis. It was the group of wags at the Alqonquin Round Table in the 1920s, the bunch that included Dorothy Parker. One asked the other to use horticulture in a sentence, and that’s what followed.
One of my favorites from the same group, was when a guy walked over to his bald headed friend and ran his hand over baldy’s head. He said, “You know, your head feels just like my wife’s butt.” Baldy then ran his hand over his head and said, “By George, you’re right. It sure does.”
You are exactly right. I knew it when I read the name. Thanks!