Giant Water Gum Syzygium francisii

Giant water gum is a rainforest tree first and a hedging plant second. In forest it passes 20 metres with a buttressed base and a broad canopy, and while it clips willingly as a young plant, nothing about a pair of shears changes what it intends to become. The foliage is the reason to want it anyway: small, glossy and densely held, finer in texture than most of the screening syzygiums, with new growth flushing bronze pink across the top of the canopy. Cream flowers give way to small mauve fruit that birds strip. Use it for large screens, windbreaks, avenues and shade.

Its natural range, and where it gets planted

It ranges naturally through the subtropical and warm temperate east and is planted from Queensland down the New South Wales coast into Victoria and the ACT, and in sheltered gardens around Adelaide and Perth. Sun or part shade both suit it. It accepts a moister site than the brush cherries will, though it still wants drainage rather than standing water, and it establishes fastest with a mulched, weed free root zone for the first two or three years. If you are hedging it, space plants 1 to 1.5 metres apart and understand that you have signed up to regular trimming for the life of the hedge, not for its first five years.

The mistake is where it goes in, not how it is grown

This tree gives little trouble in the right spot and is not much bothered by psyllid, so nearly every failure with it is a siting failure. It gets planted in courtyards, on narrow verges and a couple of metres off a slab, because in a 200mm pot it looks like a neat shrub. Ten years on it is either being butchered into a shape it will not hold, or being removed at cost, and by then the roots are into the drains. Give it room for a canopy and keep it well back from footings, service trenches and boundaries. A rough test before you dig: if you would not plant a mature fig there, do not plant this either.

The other large screening options

Acmena smithii is the other big screening lilly pilly here and the safer choice for an ordinary suburban hedge, since psyllid leaves its foliage alone and it is more forgiving of being held at a fixed height. Syzygium tierneyanum is the one for ground that stays wet. Take giant water gum when you have a long boundary, an acreage screen, a windbreak or a park to plant and want fine textured foliage on a tree with a real trunk under it. For a backyard hedge, take Acmena smithii instead. Larger stock sits in advanced trees.

Pruning for a tree or a hedge

As a hedge, cut two or three times through the warm months as each flush hardens, and keep the top narrower than the base so light still reaches the lower foliage, or the bottom metre goes hollow. As a tree, prune only for structure while it is young: take out competing leaders early and lift the low branches across several seasons rather than in one go, since a heavy single lift on a young rainforest tree leaves a thin whippy trunk that then needs staking. One controlled release feed as growth starts in spring is enough for young stock, watered in well. An established tree in reasonable soil asks for nothing beyond mulch.

Choosing a size

This plant is available in 7 sizes, from 140mm up to 400L, priced from $17.95 to $2749.00 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 lilly pilly.