"The Songs We Sang"
A Treasury of American Popular Music
by Theodore Raph    copyright 1964 

This song blossomed into full popularity over a hundred years after its birth.  The song is really quite old.  "The Yellow Rose of Texas" dates back to some years before the Civil War and was probably written shortly after our Mexican War (1846-1848).  Texas, and the additional territory we acquired from Mexico (California, Nevada, Utah, Arizona, and New Mexico), was much talked about in those days thus providing a good atmosphere for this song's later popularity. 
Originally this was, no doubt, a(n African American)  song with the "Yellow Rose" 
referring to a light (African American woman).

The song was first published in 1858 bearing the inscription "by J.K."  but it did not have much of a chance since the Civil War began soon afterwards.  When the war ended, however, "The Yellow Rose of Texas"  climbed to a fairly good popularity which seems to have lasted for about twenty years.  For the next seventy years or so, during America's periods of enormous growth and maturity, this song maintained a steady but rather low level of popularity--mostly regional. 
Along the way the song became one of the favorites of many notable people including 
Pesident Franklin D. Roosevelt.

In 1955 "The Yellow Rose of Texas became nationally prominent.  The song was revived through a fine recording of Mitch Miller's male chorus.  The recording was spirited and exciting, and America's taste was ready for it.  Miller's record sold enormously and within a few weeks this song swept the country.  "The Yellow Rose of Texas" is back on the popular-song map to stay.

"Folk Music of England, Scotland, Ireland, Wales & America"
by Lesley Nelson   www.contempator.com/folk.html

The tune was first published in 1853 by an author identified only as "J.K." It was a popular Confederate marching song during the Civil War and with the U.S. Cavalry on western outposts and along the cattle trails following the Civil War. In 1955 the tune was a hit record.

"Songs of the Wild West"
by Alan Axelrod    copyright 1991   Simon and Schuster
The Metropolitan Museum of Art /  The Buffalo Bill Historical Center

The Yellow Rose of Texas is not a flower, but a person, a servant named Emily D. West, who was indentured to Colonel James Morgan, who fought in the war for the independence of Texas from Mexico.  Emily was at Morgan's plantation seventeen miles southeast of present-day Houston when the Mexican army, under General Antonio Lopex de Santa Anna, took possession of it.  (Morgan was commanding Texas forces on Galveston Island at the time.)
On the morning of April 21, 1836, Sam Houston, in command of the Texas revolutionaries, climbed a tree and watched Emily serve Santa Anna his breakfast.  The Mexican dictator had a well-known weakness for pretty women, and Houston remarked that he hoped the girl would keep Santa Anna occupied all day.  The Texans attacked that afternoon--while Santa Anna was, in fact, with Emily.  The spectacle of a commanding general frantically running about in his red slippers was not a sight calculated to rally his troops, and the decisive Battle of San Jacinto was over in less than twenty minutes, the Texans having surprised and defeated a force more than twice their size.  This song, commemorating Emily D. West's peculiar and peculiarly interesting role in the battle, appeared shortly after the Texas Revolution and remained a favorite with soldiers, cowboys, and others who had left sweethearts behind.