It generally grows as a small shrub to 1.5 m (5 ft) high with fine narrow leaves, and is best known for its unusually coloured dark purple-violet inflorescences.

The colour of the inflorescences, short leaves, and flattened follicles which are sticky when young, help identify this species from others in the field.

[2] It is found in low shrubland in southern regions of Western Australia from Esperance in the east to Narrogin in the west, growing exclusively in sandy soils.

[2] New growth occurs in summer, and flowering ranges from November to April with a peak in February, but can be irregular in timing.

Roughly spherical with a diameter of 2–3 cm (0.8–1.2 in), the flower spikes arise from lateral stems lie partly within the foliage.

The styles are hooked rather than straight, and are initially trapped inside the upper perianth parts, but break free at anthesis.

The fruiting structure or follicle is a stout woody "cone", with a hairy appearance caused by the persistence of old withered flower parts.

When young, the follicles are greenish in colour and slightly sticky, and covered in fine white hairs, fading to tan or grey with age.

[2] The type specimen of Banksia violacea was collected by the West Australian botanist Charles Gardner on 14 December 1926 in the vicinity of Lake Grace.

[5] He placed it in section Oncostylis of Bentham's taxonomic arrangement of Banksia, giving it the specific epithet violacea in reference to the violet flowers.

[6] The species has been considered a variety of B. sphaerocarpa (Fox Banksia);[7] this view was published by William Blackall in his 1954 How to know Western Australian wildflowers.

ascendens This clade became the basis of B. subseries Longistyles, which Thiele defined as containing those taxa with very long and slender styles, smoothly convex perianth limbs without a costal ridge, and thickened margins.

Despite this, the sequence of the series was altered so that B. violacea fell between B. scabrella (Burma Road Banksia) and B. incana, and its placement in George's arrangement may be summarised as follows:[4] Since 1998, an American botanist, Austin Mast, has been publishing results of ongoing cladistic analyses of DNA sequence data for the subtribe Banksiinae.

With respect to B. violacea, Mast's results agree with its placement near B. laricina and B. incana, placing it in a clade with these two species and B. sphaerocarpa var.

[10][11][12] B. dolichostyla B. violacea B. laricina B. incana Early in 2007, Mast and Thiele initiated a rearrangement of Banksia by merging Dryandra into it, and publishing B. subgenus Spathulatae for the taxa having spoon-shaped cotyledons.

[17] Professor Margaret Bernard Sedgley of the Waite Institute suggests the species is of no value to floriculture, as the inflorescences are too small and obscured by the foliage, although she does add that the purple colour may be a worthwhile character to select for in plant breeding.