Acacia caerulescens, commonly known as limestone blue wattle, Buchan blue or Buchan blue wattle is a tree species that is endemic to south eastern Australia.
The tree grows to between in height and has a pyramidal habit with glabrous branchlets that have a fine white powdery coating. Like most species of Acacia it has phyllodes rather than true leaves. The evergreen phyllodes have an obovate to oblanceolate or sometimes narrowly elliptic shape with a length of and a width of . The lemon yellow globular flowerheads appear in racemes from November to December in the species' native range, followed by seed pods that are 5 to 12 cm long and 1.4 to 2.2 cm wide.
The species was formally described in 1989 based on plant material collected near Buchan in Gippsland.[1]
It has a limited distribution in Victoria where it is only found in the Lakes Entrance and Buchan areas. It is found as remnant populations mostly in clay soils over limestone as a part of Eucalyptus woodland communities. Its natural habitat is under threat of land clearing.