It is unlikely that the cut flowers will grow further. St. Joseph’s lily (Hippeastrum x johnsonii) is a hybrid. If somehow the flowers developed seed pods (which is uncommon even if the flower stalk was attached to a bulb), if you plant those seeds, they would probably not look like the parent. Propagation is usually through planting the offsets of the bulbs (which, after planting, will take a few years before they produce a flower).
It is unlikely that the cut flowers will grow further. St. Joseph’s lily (Hippeastrum x johnsonii) is a hybrid. If somehow the flowers developed seed pods (which is uncommon even if the flower stalk was attached to a bulb), if you plant those seeds, they would probably not look like the parent. Propagation is usually through planting the offsets of the bulbs (which, after planting, will take a few years before they produce a flower).