Flower in the month of May

There is a flower which blossoms in the month of May, it's called May Flower. Have a look at the picture.

This is the picture of a corridor garden. The plant is flowerless for almost 10 months. The bud is started to come out in April and grown up as a flower in May.

Only one flower blossoms, once in a year from a plant. The flower is stayed fresh up to the month of June.