Hackberry Celtis occidentalis

The bark gives hackberry away. Grey and smooth on young wood, it develops corky warts and raised ridges with age, a texture nothing else in a street planting quite matches. Above it sits a broad, open, deciduous canopy of coarsely toothed leaves, noticeably lopsided at the base, with small dark fruit in autumn. This is a shade and street tree chosen for sites that defeat better looking species: compacted soil, alkaline ground, wind, drought and heat radiating off bitumen.

Built for the sites nothing else will take

Plant it in full sun. It is fast growing, low water once established, and genuinely indifferent to soil type, handling alkaline clay and compacted urban fill as readily as good loam. The climate range is wide, from cold inland winters through to hot dry summers, which is why it appears in street plantings from Canberra to the Riverland. Give it space for a broad crown and it will hold that shape without staking or shaping beyond the first few years. It also tolerates trenching better than most street trees.

The failure mode is cosmetic, and it is nipple gall psyllid. In warmer districts the insect raises bumpy blisters across the foliage from late spring, and a tree can look badly disfigured by midsummer. It does no lasting damage, the tree keeps growing, and there is no spray that works at street tree scale, so this is something to accept before you plant rather than fight afterwards. One more note: keep this North American species clear in your head from Celtis sinensis and Celtis australis, which birds spread and which are declared in parts of Queensland and New South Wales.

Hackberry against the elm and the flame tree

Set beside American elm, hackberry is the lower maintenance choice by a wide margin: elm gives the better silhouette and the better autumn colour but arrives with an elm leaf beetle program in most southern districts. Set beside Chinese flame tree, hackberry is the bigger, plainer, tougher tree with no flower and far less litter. Choose hackberry when the site is hostile, the budget for aftercare is small, and shade is the whole brief. If autumn colour is the point rather than toughness, neither hackberry nor the flame tree will match a deciduous tree from a cool climate, and hackberry in particular gives a fairly quiet yellow. Buy it for the bark and the shade instead. Larger sizes are listed in advanced trees.

Structure early, then very little

Prune in late winter while the tree is dormant and the frame is visible. Young hackberries throw competing leaders and tight forks with included bark, and those are the cuts that matter: pick a leader, remove the rivals, and lift the lower limbs over several seasons to the clearance you need. Mature trees want only deadwood and the occasional rubbing branch. Feed in early spring with a complete slow release fertiliser over the root zone, water it in and mulch, though on reasonable soil an established tree will do without. Water deeply through the first two summers to set the roots, then leave it to look after itself.

Choosing a size

This plant is available in 2 sizes, from 300mm up to 100L, priced from $129.00 to $649.00 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. Every size here is established stock rather than a starter plant, so this line is intended for immediate effect rather than for growing on. Not sure which to choose? Read our guide to choosing a tree for a small backyard.