Eucalyptus erosa is a tree that typically grows to a height of and forms a
lignotuber. It has rough, fibrous to stringy, grey bark on the trunk and branches. Young plants and
coppice regrowth have narrow lance-shaped, to egg-shaped leaves long, wide and are a much darker green on one side. Adult leaves are arranged alternately, the same shade of green on both sides, lance-shaped to curved, long and wide on a
petiole long. The flower buds are arranged in groups of nine, eleven or thirteen in leaf
axils on an unbranched
peduncle long, the individual buds on a
pedicel long. Mature buds are oval, long and wide with a conical to rounded
operculum with a small point on the top. Flowering has been recorded in May and the flowers are white. The fruit is a woody, cup-shaped to hemispherical
capsule long and wide with the valves level with the rim. ==Taxonomy and naming==