The alternate, sessile leaves of Wahlenbergia nodosa are often clustered at stem tips. They are usually narrow with upturned, entire margins, here appearing fleshy. The leaves are small, becoming 5 mm long and 2 mm wide. Sometimes the smaller leaves look more triangular than oblong.
The stem tip leaves in the photo are variously curved; typically the mature leaves recurve strongly. Leaves and the similar flower sepals often have tiny sharp, mucronate tips. There may also be a few scattered spiny teeth upon leaf margins. Upper stems are red or purple and faintly hairy.
The creamy white or yellow flowers of W. nodosa have five narrow, oblong petals curving back near their tips and grooved longitudinally down the centre. The outer petal surfaces at the bud stage are coppery brown. Flowers become about 7 mm in diameter. Flowering happens after rain from spring to autumn. Moderate browsing of this plant by stock and game occurs (Vlok and Schutte-Vlok, 2010; iSpot; Bond and Goldblatt, 1984).