I rather think the song is by the recently deceased singer whose name escapes me for the moment but the chorus is:
And the teacher said..
Flowers are red young man
And green leaves are green
And there's no need to see flowers any other way
Than the way they always have been seen
And the little boy said ...
There are so many colours in the rainbow
So many colours in the morning sun
So many colours in the rainbow
And I see every one.
Wait .. his name is Harry Chapham (won't guarantee the spelling)