I have seen similar flowers to this longifolium labeled as longifolium var roezlii. The narrower foliage goes with where I have seen that name used. Nice growing, and you will find as the plant matures and becomes a larger specimen, Phrag longifolium and all its horticultural and taxonomic varieties can have very long lived flower stems, capable of producing many flowers, usually one at a time, over many months, sometimes years. Your plant looks to be nicely grown, well done.