Flowers in the Snow
Gulf Coast Highway ("This is the only place on earth bluebonnets grow. / Once a year they come and go at this old house here by the road.")
The Trumpet Vine
Ye Banks and Braes o' Bonnie Doon

Songs with lines or verses about flowers:
My Darling Clementine
Barbara Allen
Loch Lomond
Stardust
In the Shade of the Old Apple Tree
California, Here I Come

Genie