Graderia scabra is a perennial, hemi-parasitic, herb to dwarf shrub, 200–600 mm high, usually with a woody rootstock. The finest roots bear tiny haustoria, structures that attach to the roots of other plants (S.J. Smithies pers. obs.). Many herbaceous stems, up to 650 mm long, are held erect or sometimes trailing. These are often branched near the base and can be hairy or not. Leaves are green, opposite or nearly alternate, often overlapping and sessile (stalkless). In shape they are ovate-elliptic, about 50 × 15 mm. The leaf apex is acute (pointed), whereas margins are entire (undivided) or with a few large, acute teeth. There are 3–5 veins, prominent on the under surface.

Fig.2: Graderia scabra, flowers on a trailing stem. (Photo Kate Braun)

Flowers are usually pink but can range via mauve to purple, or be almost white, red or rarely blue. They are thinly covered in fine, white hairs. The corolla tube is narrowly funnel-shaped, up to 20 mm long. It bears 5 spreading lobes that are broadly rounded, 4–9 mm long. The tube is often a stronger colour outside than the lobes. The flower mouth is open and may be compressed from above. Throat colour is usually lighter below, often white, but may be darker above. Veins in this area are often a dark pink or reddish, some extending onto the lobes. Anthers are held just inside the roof of the corolla tube. The longer, filiform style is also placed here and the tip bends downwards in the tube mouth, ending in a tiny, rounded stigma.

Fig.3: Graderia scabra, side view of a flower, showing pollen dusted on lower lobes and the stigma. (Photo Kate Braun)

Fruit is a small, pointed capsule, about 7 mm long and wide, and strongly longitudinally flattened. The many seeds are minute. Flowering occurs in spring and early summer, from August to December.