The flexed stem of Gladiolus mortonius is usually unbranched, the inclined spike comprising eight to sixteen two-lipped flowers. The bracts are pale green or yellow-green to blue-green, the outer one about 5 cm long, acutely pointed. The inner one is three-quarters as long or up to equal in length with a forked tip.
The flowers are pink to salmon, their tepals unequal. The upper three are larger, lanceolate to ovate, their margins wavy. The dorsal tepal arches over the three-branched style and the three stamens immediately below that. The lower tepals have a red median streak as well as a few reddish, parallel lines alongside it.
The oblong anthers are usually purple, their pollen whitish. The oblong ovary is up to 5 mm long, the three-lobed capsule ensuing from it up to 32 mm long.
Flowering happens from late summer to after middle autumn (Goldblatt and Manning, 1998; Manning, 2009; iNaturalist).