Plants 50-100 cm. Corms tunicate, ca. 20 mm diam.; tunic coriaceous, fragmenting into irregular pieces, rarely ultimately becoming fibrous. Stems simple. Leaves ± reaching base of spike; blade plane, lanceolate, sometimes narrowly so, 5-22 mm wide. Spikes 10-20-flowered; spathes unequal, outer 25-35(-50) mm, inner ± 2/3 outer. Flowers unscented, weakly distichous; perianth tube obliquely funnel-shaped, 10-12 mm; tepals reddish purple with narrow median white streak on outer 3 tepals, unequal, dorsal tepal 30-40 × 14-19 mm, inner lateral tepals joined to outer tepals for ca. 3 mm, 28-35 mm, outer 3 tepals connate for ca. 2 mm, outer lateral tepals 18-25 mm, outer median tepal 24-28 mm; filaments 12-15 mm; anthers 10-13 mm; style branching opposite distal 1/3 of anthers; branches ca. 2 mm. Capsules oblong, 18-24 mm. Seeds broadly winged, 4-6 mm diam.
Gladiolus communis is a garden escape. In regional floras it is sometimes confused with the southern African G. papilio Hooker; the resemblance is entirely superficial. Plants of G. communis found in North America have traditionally been treated as G. byzantinus, which differs little from G. communis except in degree of robustness. Distinction at even subspecific rank does not seem warranted.