It sounds to me as though you are growing Yucca filamentosa, also called Adam's needle, which has a basal rosette of straplike evergreen leaves and is hardy to Zone 4. It thrives in the long, hot summers of the southeastern United States, where it's native. It prefers full sun and well-drained, relatively dry soil. It can take 5 years for its tall spikes of creamy white flowers to appear, so patience may be all that is required for your yucca to bloom. After blooming and fruiting, the rosette dies, sending up side shoots, known as pups, that make new plants around the former base. When your plant finishes blooming, you can trim off the flower stalk, or you can leave it and enjoy the interesting seedpods.