Gladiolus longicollis subsp. platypetalus is a cormous perennial reaching heights when in flower between 30 cm and 80 cm. The corm is cone-shaped, covered in light brown fibres.
Three leaves are grown annually. The lowest one is the biggest, about two thirds of the inflorescence length. The cross-section of this leaf is circular to cross-shaped and four-grooved. The other two are smaller stem-leaves, the top one's tip reaching to the lowest flower.
The subspecies distribution is in the east of South Africa, from the northeast of the Eastern Cape, the east of the Free State, KwaZulu-Natal, Mpumalanga, Gauteng, and Limpopo, as well as in some neighbouring countries. This flower was spotted south of Dullstroom in October.
The habitat is grassland from sea level to altitudes around 3000 m. The habitat population of the subspecies is deemed of least concern early in the twenty first century (Goldblatt and Manning, 1998; Pooley, 1998; Lowrey and Wright, 1987; iNaturalist; http://redlist.sanbi.org).