Minstrel Version (1858)
There's a yellow rose in Texas that I am going to see,
No other darkey knows her, no darkey only me;
She cried so when I left her, it like to broke my heart,
And if I ever find her we never more will part.  [bad word] 
She's the sweetest rose of color this darkey ever knew,
Her eyes are bright as diamonds, they sparkle like the dew,
You may talk about your Dearest May, and sing of Rosa Lee,
But the yellow rose of Texas beats the belles of Tennessee.
Where the Rio Grande is flowing, and the starry skies are bright,
She walks along the river in the quiet summer night;
She thinks if I remember, when we parted long ago,
I promis'd [bad word] back again, and not to leave her so.  [bad word] 
Oh! now I'm going to find her, for my heart is full of woe,
And we'll sing the song together, that we sung so long ago;
We'll play the banjo gaily, and we'll sing the songs of yore,
And the yellow rose of Texas shall be mine for evermore.  [bad word]  

The expressions "high yellow" or simply "yellow" were used during this time period to refer to a light-skinned African-American with significant Caucasian ancestry, and the original lyrics may have referred to a biracial woman as the "yellow rose".
Some later versions of the song replaced phrases such as darky and rose of colour with soldier and little flower. In Mitch Miller's version No other darky knows her, no darky only me was replaced with Nobody else could miss her, not half as much as me and sweetest rose of colour this darky ever knew was replaced with sweetest little rosebud that Texas ever knew. Dearest May was replaced with Clementine and, beats the belles of Tennessee was replaced with, is the only girl for me.

Johhny Horton version
Civil War song
The song became popular with Confederate Army troops, especially those from Texas, though the last verse and the [bad word] are slightly different.
(Last verse)
Oh my feet are torn and bloody, and my heart is full of woe,
I'm going back to Georgia, to find my Uncle Joe,
You may talk about your Beauregard, sing of General Lee,
But the gallant Hood of Texas, played [bad word] in Tennessee.
This refers to famous Confederate generals Joseph Johnston, Robert E. Lee, P. G. T. Beauregard, and John Bell Hood.
The [bad word] substitutes the word, darky, with soldier. The same substitution is made throughout the song.

There's a yellow rose in Texas that I am gonna see
No other soldier knows her, no soldier only me
She cried so when I left her, it like to broke my heart
And if I ever find her we never more will part

She's the sweetest rose of colour this soldier ever knew 
Her eyes are bright as diamonds, they sparkle like the dew
You may talk about dearest May and sing of Rosa Lee
But the Yellow Rose of Texas beats the belles of Tennessee

Where the Rio Grande is flowin, and starry skies are bright
She walks along the river in the quiet summer night
She thinks if I remember when we parted long ago
I promised [bad word] back again and not to leave her so

She's the sweetest rose of colour this soldier ever knew 
Her eyes are bright as diamonds, they sparkle like the dew
You may talk about dearest May and sing of Rosa Lee
But the Yellow Rose of Texas beats the belles of Tennessee

Oh my feet are torn and bloody, and my heart if full of woe,
I'm going back to Georgia, to find my Uncle Joe,
You may talk about your Beauregard, and sing of Bobbie Lee,
But the gallant Hood of Texas, he played [bad word] in Tennessee. 

She's the sweetest rose of colour this soldier ever knew 
Her eyes are bright as diamonds, they sparkle like the dew
You may talk about dearest May and sing of Rosa Lee
But the Yellow Rose of Texas beats the belles of Tennessee