The flowers of Lobelia linearis grow in single racemes or branched panicles. The small blue or purple flowers have variable white patches at the base of the three attractively shaped lobes on the larger lower lip. The two tiny lobes of the upper lip are narrowly elliptic. The corolla may measure 1 cm to 1,5 cm in length. The corolla tube widens slightly towards the mouth; its outside may be hairy.

Flowers are found all through spring and summer, a little into autumn. These flowers were seen in October on the Rooiberg in the southern Cape (Vlok and Schutte-Vlok, 2010; Manning, 2007).