Most winged bean varieties will not flower until daylight length is less than 12 hours, yet they are sensitive to frost.

Ditto on Drloyd's comments. There are supposedly day neutral winged beans sold by several vendors, but generally winged beans will not flower until close to the equinox, when days are short. Since the equinox has just passed, check your plant carefully, you will probably find flower clusters beginning to emerge from the leaf axils on new growth.

The other possibility is that the plant was over fertilized, which can result in heavy foliage, but delayed blooming.

Virtually every part of the plant is edible, so if the vine fails to flower, you can always eat the young leaves as a cooked green.