Lobelia neglecta grows trailing or erect stems bearing short-stalked to about stalkless, mostly alternate leaves, sometimes dropped off lower stem parts.
The leaves are oblong to elliptic or ovate, the tips rounded to obtusely pointed. The margins may be entire, slightly toothed and even small-lobed, usually rolled under. The upper surfaces are bright green, sometimes shiny although rough, the lower surfaces paler. Sparse long hairs may occur mainly along the margins and below. The leaves are about 1 cm long and 4 mm wide (Euston-Brown and Kruger, 2023; Bond and Goldblatt, 1984; iNaturalist).