Sweet Gum Liquidambar styraciflua

Sweet gum grows fast and strongly pyramidal when young, broadening with age into a large shade tree with corky ridged bark. Its signature is the glossy star-shaped leaf, which turns in autumn to anything from butter yellow to deep burgundy. Seedling-grown trees vary, so two side by side in the same row can colour completely differently, which is either a charm or a problem depending on the job. Use it for serious shade and autumn colour on acreage, in parks and at the back of a large block.

Room is the whole requirement

Full sun, moderate water and some depth of soil to work with. It grows well through Victoria, the New South Wales tablelands, Adelaide, Canberra and cooler parts of south-east Queensland, and the colour sharpens where autumn nights get properly cold. Give it a deep, open root run and steady moisture through the first few summers while it establishes, then it looks after itself. Autumn colour is a lottery unless you buy a named clone, so where a particular shade matters, choose your tree while it is in leaf.

The one real failure mode is putting it too close to anything built. Liquidambar develops aggressive surface roots that lift paving, paths, driveway edges and lawn over time, and can find their way into old drainage lines. Set it well back from hard surfaces and boundaries, and never in a narrow verge or a courtyard. The woody spiked seed capsules are the second reason to keep it away from people: they drop in quantity, they are painful underfoot, they block gutters and they fly out from under a mower. On acreage none of this matters. In a small garden it is the wrong tree, whatever the autumn photographs suggest.

What to plant instead in a small garden

If the block cannot take that scale of root system, River Birch - Betula nigra Summer Cascade gives you deciduous character, peeling cinnamon bark and soft yellow autumn colour at a size that fits a courtyard or a pond edge, and it accepts damper heavier ground than a liquidambar enjoys. Where the site is hot, dry and inland and shade matters more than colour, Arizona Ash - Fraxinus velutina throws a similar canopy without the seed capsule litter, though its timber is brittle and needs formative pruning. Keep the liquidambar for the site that genuinely has room. More in feature trees.

Winter shaping and spring feeding

Prune in winter while it is bare. The work worth doing is formative: hold a single central leader, remove competing co-dominant stems early, and lift the lower canopy gradually over several seasons as the tree gains height. Do not top it, since a headed liquidambar responds with a mass of weak upright shoots that spoil the outline and shed in storms. Feed in early spring with a balanced slow-release fertiliser applied out to the drip line, and mulch generously over the surface roots while keeping the material off the trunk.

Choosing a size

This plant is available in 12 sizes, from 200mm up to 200L, priced from $43.95 to $1589.00 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. The smaller pots hold younger plants that cost less each and establish quickly, which suits hedges, screens and mass planting where the plant count adds up. The larger sizes carry several more years of growth on the farm and give height and presence straight away, which is what you want for a single feature position or a screen that cannot wait. Not sure which to choose? Read our guide to choosing a tree for a small backyard.