Shame one can't get blue roses, apart from the ones that have been left to soak up blue dye and don't last and are not inordinately nice.

Roses red and roses white
Plucked I for my love’s delight.
She would none of all my posies--
Bade me gather her blue roses.

Half the world I wandered through,
Seeking where such flowers grew
Half the world unto my quest
Answered me with laugh and jest.

Home I came at wintertide,
But my silly love had died
Seeking with her latest breath
Roses from the arms of Death.

It may be beyond the grave
She shall find what she would have.
Mine was but an idle quest—
Roses white and red are best!

--Rudyard Kipling