Banksia idiogenes is a tufted shrub up to about 70 cm (28 in) in diameter with hairy stems, but does not form a lignotuber.

There are between twenty and twenty-five triangular lobes up to 19 mm (0.75 in) long on each side of the leaves and the lower surface has a prominent network of veins.

[2][3][4] This species was first formally described by Alex George in 1996 in the journal Nuytsia and given the name Dryandra idiogenes, from material he collected near Newdegate in 1986.

[5] The specific epithet (idiogenes) is an ancient Greek word meaning "distinctive" or "peculiar", in reference to this species' unusual bracts and strongly scented red and white flowers.

[2][3][4] This banksia is classified as "Priority Two" by the Western Australian Government Department of Parks and Wildlife[2] meaning that it is poorly known and from only one or a few locations.