Eucalyptus johnsoniana is a mallee that typically grows to a height of and forms a
lignotuber. It has smooth greyish brown bark, sometimes with rough, flaky to fibrous bark on the lower part of the trunk. Young plants and
coppice regrowth have dull bluish green, egg-shaped to elliptic leaves that are long and wide. Adult leaves are lance-shaped, long and wide on a
petiole long. The flower buds are arranged in leaf axils in groups of seven on a
peduncle long, the individual buds on
pedicels long. Mature buds are oval to pear-shaped, long and wide with a rounded
operculum. Flowering occurs from July to August or from October to January and the flowers are creamy white. The fruit is a woody, shortened spherical
capsule with an unusually small opening. ==Taxonomy and naming==