Eucalyptus spathulata is a low-branching mallet with a dense crown that typically grows to a height of 8–12 m (26–39 ft) but does not form a lignotuber.

[2][3][4][5] Eucalyptus spathulata was formally described in 1844 by botanist William Jackson Hooker in his book Icones Plantarum, from specimens collected near the Swan River by James Drummond.

[6][7] The specific epithet (spathulata) is from the Latin word spathulatus, meaning spoon-like or a broad rounded upper part tapering gradually downward into a stalk.

[2] Two subspecies are recognised by the Australian Plant Census: Swamp mallet is found on flats, broad valley floors, on rises, in and around saline depressions and along the edges of salt lakes in the southern Wheatbelt and inland Great Southern regions of Western Australia where it grows in sandy or sandy-clay soils over granite.

Other associated species include Bossiaea halophila, Gahnia ancistrophylla and Brachyscome lineariloba, all well suited to calcareous, saline low-lying areas.

The tree's wood is dense, hard and pale brown in colour and can be used as a source of fuelwood and craftwood.