Gum Tree Eucalyptus moluccana

Grey box is a large evergreen eucalypt with a straight trunk and a fairly open, spreading crown. The bark identifies it: pale grey, rough and closely fissured on the trunk and larger limbs, then shedding cleanly to smooth white on the upper branches. Adult leaves are dull grey green rather than glossy, and the white flowering is heavy enough that beekeepers rate it for nectar and honey. Its main use now is habitat and revegetation planting, particularly on the clay soils of the Cumberland Plain.

Provenance work on heavy clay

Specify grey box when a plan calls for a Cumberland Plain or western Sydney local species. Grey box woodland is a listed endangered ecological community, so this eucalypt appears constantly in offset planting, roadside restoration and habitat work through the Sydney basin, the western slopes and inland Queensland. It handles the heavy clay those districts are built on, grows fast in full sun and needs little water once established. It becomes a large shade tree in time, so keep it well away from buildings, drains and overhead services from the outset. It is a nectar source in flower and supports hollow dependent wildlife as it ages.

The failure mode with advanced stock is the root ball. A eucalypt held in a large container long enough to reach saleable size can carry circling roots, and a tree planted with those roots intact looks fine for years and then leans or blows over in a storm. At planting, open the outside of the root ball, cut any root circling the pot wall, set it at the depth it grew, and stake low and loosely for one season only.

Grey box or blue gum for a big native

The closest comparison here is Sydney blue gum. Blue gum wants deep, moist, better drained slopes and gains height faster than almost anything else on this list, while grey box is the species for heavy clay, drier western sites and restoration plantings with a provenance requirement. If the block is small, neither is right, and pink gum is the smaller scaled option for dry ground. Choose grey box when the brief is ecological rather than ornamental. Grey box also flowers heavily enough to matter in a bee or habitat plan, which is not why anyone plants the others. Choose it when provenance and vegetation community are written into the brief. It sits with the rest of the natives.

Establishment and the first three years

Prune in late winter or early spring and keep it structural: remove co dominant leaders and included bark unions while the wood is small, and leave the rest of the crown alone. Mature eucalypts do not respond well to reduction pruning, so the tree you shape in year two is the tree you keep. Water deeply and infrequently through the first two summers to draw roots down into the clay. Feed lightly if at all, using a low phosphorus native formulation in early spring, and mulch a wide ring while keeping it clear of the trunk. Avoid staking high or leaving ties on beyond the first year.

Choosing a size

This plant is supplied in one size, 200L, at $2189.00 per plant. The size shown is the pot it arrives in, which is the rootball, not the height of the plant. Not sure which to choose? Read our guide to Australian native trees for shade.