Now never marry a soldier, a sailor or a marine
But keep your eye on the Sinn Féin boy with his yellow, white and green.

See this thread about the Parnellite tricolour:

In 1883 a Parnellite tricolour of yellow, white and green, arranged horizontally, is recorded.

This phrase "is recorded", which appears in every online reference to the Parnellite tricolour, suggests it was uncommon - was it? Or is it used here because 'green white and orange' doesn't rhyme ur scan and 'orange white and green' is not in the usual order.