That is the 'story' as told by the UT marketing dept. Another similar but much older version is when the team captain, (was it really Charles Moore of the first squad?) was asked by a sportswriter what the team colors were, he had no answer. Football was merely a club sport in those days, sort of like bass tournament fishing is now. Anyway, thinking on his feet, the good captain looked around and planted all around and in full autumn bloom were flower beds of orange and white mums; not the 'daisey's on a hill'. I suppose the daisey thing sounds a bit more romantic to a advertising and marketing type instead of it just being the flowers that happened to be in UT's flower beds and were in bloom.
Which is what? I don't know. I find the mums story, which was all I ever heard until recently, easier to believe. But, it's possible that was the 'made up' story until someone turned up daiseys doing research in the bowels of the old graduate library.
Either, or, tomato, tomahto.