This shrub grows up to 4 m high and 2 m wide, lobed leaves grow to 150 mm in length. The flower spikes are orange in colour, growing 150 mm high and 90 mm wide. B. ashbyi flowers from September to November.
An assessment of the potential impact of climate change on this species found that its range is unlikely to contract and may actually grow, depending on how effectively it migrates into newly habitable areas.
^Fitzpatrick, Matthew C.; Gove, Aaron D.; Sanders, Nathan J.; Dunn, Robert R. (2008). "Climate change, plant migration, and range collapse in a global biodiversity hotspot: the Banksia (Proteaceae) of Western Australia". Global Change Biology. 14 (6): 1–16. doi:10.1111/j.1365-2486.2008.01559.x.
^Sweedman, Luke; Merritt, David (2006). Australian Seeds: a Guide to Their Collection, Identification and Biology. Collingwood, Victoria: CSIRO Publishing. p. 202. ISBN0-643-09298-6.