Refers to the romanticization of the pre-civil war south. The term alludes to soft lighting and flower scents. It has evolved as a synonym for "euphemism."
Allegedly, the phrase was coined by the writers of "Gone With The Wind" to descibe the scene at Twelve Oaks when the confederates found out that war had been declared. It refers to the men's eagerness to battle and the women's eagerness to 'claim' their confederate soldier before he left.
"You can drop the moonlight and magnolia, Scarlett!
So things have been going well at Tara, have they?"
-Rhett Butler, Gone with the wind
(When Scarlett wore a dress made of green velvet drapes to Atlanta to try and get money from Rhett to pay taxes on her home, Tara, she smiled sweetly and claimed to have eveything she cold hope for and "not a care in the world." Rhett noticed her hands, calloused from picking cotton, and knew she was lying.)