Wattle Acacia implexa

Lightwood is not one of the fluffy yellow wattles that flower in July and fall apart a decade later. It makes an open, upright small tree with long curved sickle shaped phyllodes, flowers in summer and autumn in pale cream globes, and lives considerably longer than the short lived acacias that give the genus its reputation. The seed pods twist and coil tightly as they dry, which is the easiest way to confirm it. It is grown for windbreaks, shelterbelts, revegetation work and screening on rural blocks.

Room for a tree that suckers

Full sun, free draining soil, and very little water once it is away. This is a dry country plant and it copes with exposed sites and poor ground that would stall most trees. It grows through the eastern states across a wide range of climates and tolerates frost, heat and wind. Fast growth means a shelterbelt closes quickly, and planting a mixed row with slower species behind it gives you shelter now and structure later. In a windbreak, space it wide enough that each tree keeps a full crown, since a crowded row draws up tall and thin and delivers less shelter at ground level.

The failure mode is suckering. Lightwood throws new shoots from its roots, especially where soil has been disturbed or roots have been cut by a mower, a trencher or a plough, and a single tree can put a thicket up through a lawn or a garden bed. In a shelterbelt or a revegetation planting that is a benefit and part of why it is specified. In a suburban backyard it is a running battle you will not win, so site it accordingly and do not cultivate over the root zone.

Lightwood, gossamer and golden

It is regularly confused with blackwood, Acacia melanoxylon, which is darker, denser and much heavier in the trunk. Lightwood is the airier of the two and better suited to dry, exposed country. Within this batch, Acacia floribunda is the softer, weeping, faster screen for a garden scale planting, and Acacia pycnantha is the showier flowerer for a dry bank. Choose implexa where the planting has to last: a windbreak, a paddock shelterbelt or a revegetation job where longevity and suckering are both wanted. Its summer and autumn flowering also fills a gap the other two leave, since both of those are finished by spring. The wattle range lists the others.

Formative pruning while it is young

Decide early whether you want a single trunked tree or a multi stemmed screen and prune to that within the first two or three years, while the cuts are small. A leader chosen and held then saves major limb removal later. Prune after flowering, and keep cuts within leafy growth rather than into bare wood. Feeding is rarely needed and phosphorus rich fertilisers should be avoided altogether. Remove root suckers at ground level as they appear if the tree stands anywhere near lawn or paving. Water through the first summer and then stop, since continued irrigation pushes soft growth and more suckering.

Choosing a size

This plant is available in 7 sizes, from 75mm up to 430mm, priced from $16.95 to $269.00 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 Australian native trees.