[3] Individual plants may be up to 90 cm (35 in) in diameter and up to 1 metre (39 in) high when in flower, and consist of sharp spines, all pointing out from the centre.

Yellow flowers may also be present, located on long, narrow, and strong stems.

[4][5] A. colensoi is endemic and can be found in both main islands of New Zealand, typically in altitudes from 900 to 1,500 m (3,000 to 4,900 ft).

They are often found in moist conditions on sites featuring a mix of snow tussock scrub, grassland, and herbfields.

[5] The decline of A. colensoi due to browsing from rabbits was noted as early as 1883.