Your plant is a variety of crocosmia. Your noticing its resemblance to a gladiolus is right on the mark-both plants are members of the iris family. 'Lucifer' crocosmia is hardy in Zones 6-9. Plant crocosmia in full sun and well-drained soil. In northern ranges of Zone 6, cover the plant with several inches of mulch in winter, just after the soil freezes, to protect the overwintering corms.