[3] This species is a perennial herb that forms stout rosettes of spiky leaves reaching 50—80 cm.

[4] It is a "spear grass" with stems that can grow to 80 cm, producing a dense rosette at the top.

These stems are arranged in a subfellate to pinnate shape and tend to be a yellow - green colour.

In his description Oliver noted that this species was most similar to A. squarrosa in its narrow leaves and downturned terminal bract segments, but the finely-toothed terminal bracts are much longer (up to 30 cm) and the leaves are always bipinnate.

[4]Walter Oliver first described the plant in 1956, from a type specimen collected Waiau tussock grassland.

[6] Spear grass is well suited to alluvial terraces, basins, or rolling hills, and does not like humid climates or being wet.

The land is more exposed to strong winds, meaning Aciphylla subflabellata is suited to this type of environment.

[11] Another threat is the amount of weeds that are overtaking the habitat, causing Aciphylla subflabellata populations to further decrease.

These studies also revealed some data about Aciphylla subflabellata such as where the species might be found in some parts of Canterbury.

This species' status under the Department of Conservation's NZTCS system is "At Risk – Declining"[1] It may be naturally uncommon over most of its range, but much of its habitat has been modified for pastoral farming and like most Aciphylla species it is vulnerable to browsing by stock, rabbits, and hares.