Carmine is a shade of red. I think this refers to the red tulip changing from a green bud to a red flower. So therefore, putting on her carmine suit as in turning into a beautiful shade of red. This might symbolize change and growth.
This is on the grounds that in the poem it alludes to a tulip. Put on her carmine suit in all probability implies the tulip sprouts and abandons a green bud into a red blossom.
