Strange . You must be feeling pretty disappointed. They should be just coming into flower without leaves, and the leaves appear when the flowers have finished. Mine have been in the same pot for about 12 years with the pot tucked in a south west facing corner and the original half dozen now have 15 flowers! They are very crowded and are pretty dry all summer when the leaves have gone.
Others I've seen were in the ground but also in front of a south facing wall. I'd try high a potash feed while the leaves still there and give them another season, and if they still don't flower try moving them as suggested.

Thanks. I was surprised to see foliage instead of flowers. Do you mean feed now before the foliage dies down. Plants have been all to pot this year. I had a hippeastrum in the greenhouse resting from last Christmas and it threw up a flower spike in August so it's back resting again.

Wait a bit longer - mine haven't flowered yet, though the ones in the large pot are just showing buds now, and on inspection, the ones in the small pot do have buds, but they are still low down, though the leaves are already disappearing. If they still don't flower, maybe the soil is too rich or too damp for them - they do best in dry conditions and sandy, light soil and in full sun. The best ones I've ever seen were growing right up against the foot of a wall in full sun, and the soil there was very dry and very light - they'd spread right along the bottom of the wall.

Not hundred percent sure about feeding now - so much depends on the unpredictable weather. Maybe make sure in future they are well drained and sunny (in a pot if need be if that's the only access to a south facing sheltered spot) and if where they are isn't suitable, move them when the leaves have died back if they still didn't flower. My rather neglected ones are in a 10.5" pot and flower their hearts out.

No point feeding now, the leaves will start to die back very shortly, if they're not already doing so. Feeding is best during summer, when the leaves are growing strongly.