Vintage 50s-60s Blue And white Stripe Embroidered Pink Flowers House Dress Rare

Dress does not have a size listed but the mannequin is a U.S. size 2-4. It fits the mannequin well so would be a size S. It is in good condition. Zipper works fine. There is a button hole on the back of the dress near the top where the zipper ends. I do not see a button on the dress so I am not sure what it is for.