The inflorescence of Radinosiphon leptostachya is a zigzagging spike usually comprising four to twelve flowers in two opposite arrays. The spike is secund, the slender flowers facing to one side. The flowering stem may be simple or up to three-branched. There are stem-leaves below the inflorescence, reducing in size higher up.

The specific name, leptostachya, is derived from the Greek words leptos meaning slender and stachya meaning an ear of corn, referring to the inflorescence shape. The generic name, Radinosiphon, is derived from the Greek words radinosus, also meaning slender and siphon meaning tube, making the flowers doubly slender.

Blooming happens mostly in the second half of summer, sometimes throughout summer into early autumn (Onderstall, 1996; iNaturalist; JSTOR; https://wildflowernursery.co.za; https://www.pacificbulbsociety.org; https://www.zimbabweflora.co.zw).