The 10 best Australian natives for supressing weeds in your garden
The most effective long-term weed control in a native garden is not spraying, but denying weeds the light, space and soil they need to establish in the first place.
Running postman (Kennedia prostrata) trained flat across a bank, one of the natives that covers bare ground and shades out weed seed while flowering for wildlife.
Weed suppression is several different jobs and matching the mechanism to the site is the whole game. The ten plants here are grouped by how they suppress weeds and where they do it.
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How plants suppress weeds
There are four main ways of using natives as weed suppressors. It does take some time, so patience is required, but once in place these plants do a great job at keeping weeds at bay.
1. Shading out germinating seed
1 to 2 growing seasons to full cover
Dense low groundcovers form a living mulch that denies light to weed seedlings before they can establish. This is the most reliable mechanism for a home garden and covers most of the plants here.
Blue star creeper (Lobelia pedunculata) forms a low dense mat of foliage and starry flowers that shades out weed seedlings before they can take hold.
2. Occupying the ground completely
1 to 2 seasons as clumps knit together
Tightly clumping plants and prostrate shrubs pack the soil surface so densely that weeds cannot find room to root between them, particularly in mass plantings.
Knitted, dense shrubs provide no space or light for weeds to germinate.
3. Outcompeting for light and water
Establishes in 1 season, thickens after
Fast, vigorous plants simply outgrow weeds, taking the light and moisture first. Competitive native grass swards work this way.
A dense native grass sward outcompetes weeds by taking the available light and moisture first, leaving little for weed seedlings to draw on.
4. Litter smothering
Several years, as the canopy and litter mature
Some plants drop a dense, slow-rotting litter that physically blocks small seeds from germinating beneath them. This is why bare ground persists under certain trees.
A dense, slow-rotting leaf litter physically blocks weed seed from germinating beneath the canopy, and provides camouflaged habitat for ground-dwelling wildlife such as this grey ringlet (Hypocysta pseudirius).
John Tann from Sydney, Australia, CC BY 2.0, via Wikimedia Commons
Dense groundcovers — shading out weed seed1. Creeping boobialla (Myoporum parvifolium)
Shades out seedHot, dry, sunny
Creeping boobialla is the first plant to reach for on hot, dry, open ground. It spreads two to three metres across by surface runners, forming a flat mat of fine bright green foliage studded with small white flowers. Because it roots as it spreads and does not self-seed aggressively, it covers bare soil fast but stays easy to pull back at the edges.
Creeping boobialla (Myoporum parvifolium) — a flat, fast-spreading mat for hot dry ground that covers bare soil before weeds can establish.
Where it works
Best on dry banks, rockeries and the exposed edges of a garden where little else will knit together. It needs good drainage and full sun and will thin out in shade or wet ground, so it is not the plant for a damp or shaded bed.
2. Native violet (Viola hederacea)
Shades out seedDamp, shaded
Native violet covers the conditions most groundcovers hate: damp shade and part shade beneath trees and shrubs, where weed suppression is usually hardest to achieve. It forms a soft dense carpet of kidney-shaped leaves scattered with white and purple flowers for much of the year. It spreads by runners and light self-seeding, filling gaps quickly once established.
Native violet (Viola hederacea) forms a flowering carpet in damp shade, suppressing weeds in the difficult ground beneath trees and shrubs.
Where it works
Ideal under established trees, on the shaded side of the house and along moist garden edges. Suits cool temperate through to subtropical gardens. It will struggle in hot, dry, fully exposed positions, which is exactly where creeping boobialla takes over.
3. Kidney weed (Dichondra repens)
Shades out seedSun to part shade
Kidney weed is the most climate-flexible groundcover on this list, occurring naturally across every mainland state and Tasmania. It forms a dense low mat of rounded leaves that roots at the nodes as it spreads. It takes light foot traffic, which makes it useful between pavers, along paths and as a soft lawn alternative.
Kidney weed (Dichondra repens) forms a dense low mat that roots as it spreads, covering bare ground and taking light foot traffic.
Where it works
A genuine all-rounder for sun to part shade in most Australian gardens. Plant around 30cm apart for a lawn substitute, closer for quicker weed-excluding cover in a bed. It is the safe default when you are not sure which groundcover a spot will suit.
Prostrate shrubs — a dense woody mat
4. Prostrate grevillea (Grevillea 'Poorinda Royal Mantle')
Occupies the groundSun, well-drained
Where a low herbaceous groundcover covers small gaps, a prostrate grevillea blankets a large area with a dense woody canopy that excludes weeds while flowering for birds. 'Poorinda Royal Mantle' is the long-standing benchmark, spreading to around six metres in two to three years with glossy dark leaves, coppery new growth and red toothbrush flowers through winter and spring. 'Bronze Rambler' is a similar alternative with bronze-tinted foliage.
A prostrate grevillea forms a dense weed-excluding canopy across a bank while flowering through the cooler months for honeyeaters.
Where it works
Excellent on banks, embankments and large open beds in full sun with good drainage. It grows in all but tropical zones and tolerates drought and frost once established. Give it room and keep it clear of paths where it can sprawl over an edge.
5. Native pigface (Carpobrotus rossii)
Occupies the groundHot, exposed sand
Native pigface handles the harshest suppression job of all: hot, exposed sand and rocky slopes where reflected heat and salt would stress almost anything else. Its thick triangular succulent leaves store water and form a complete mat that smothers weeds outright. One caution matters here: confirm you are buying native Carpobrotus rossii and not the introduced South African Carpobrotus edulis, which is itself a coastal weed.
Native pigface (Carpobrotus rossii) forms a complete succulent mat that smothers weeds on hot exposed sand and slopes where little else survives.
Where it works
The specialist for coastal dunes, hot slopes and dry sandy ground in full sun across southern Australia. It will rot in shade or heavy wet soil, so keep it to the hot, free-draining positions it was built for.
Suppression starts after establishment
None of these plants suppresses weeds on the day it goes in. Every one works by eventually covering or occupying the ground, which takes a full growing season or two. Through that first year the bare soil between young plants is exactly the open ground weeds exploit, so plan to weed and mulch until the plants knit together.
6. Mat rush (Lomandra longifolia)
Occupies the groundSun or shade, anywhere
Mat rush is the toughest all-rounder for weed suppression through mass planting. Its dense strappy clumps pack tightly together when planted in drifts, leaving no open ground between them for weeds to colonise. It tolerates sun or part shade, wet or dry soil, drought, frost and coastal exposure. Because it is strictly clump-forming it carries no spread risk at all.
Mat rush (Lomandra longifolia) planted in drifts packs the ground so tightly at the base that weeds find no room to colonise between the clumps.
Where it works
Almost anywhere, which is what makes it so useful. Plant in generous drifts spaced so the mature clumps will just touch, and the planting will close over into a continuous weed-excluding band. Nationwide climate tolerance.
7. Knobby club-rush (Ficinia nodosa)
Occupies the groundDamp, coastal, poorly drained
Knobby club-rush does for damp and poorly drained ground what mat rush does for dry: it forms dense rounded clumps of fine green stems that occupy the soil surface and exclude weeds. It thrives in the wet, saline and badly drained positions that defeat many other plants, including coastal sites and the low spots where water sits.
Knobby club-rush (Ficinia nodosa) forms dense clumps of fine green stems that exclude weeds on the damp, coastal and poorly drained ground where mat rush would struggle.
Where it works
The clumping choice for damp, coastal or poorly drained ground across southern and eastern Australia. Mass plant it the same way as mat rush, spaced to close over at maturity. It pairs naturally with mat rush, taking the wet spots while mat rush covers the drier ground of the same garden.
Competitive sward — outcompeting for light and water
8. Weeping grass (Microlaena stipoides)
OutcompetesSun to part shade lawn
Weeping grass is one of the very few native grasses that makes a genuine mowable lawn, and as it establishes it forms a dense competitive sward. It grows in sun to part shade, tolerates moderate foot traffic and stays green with far less water and feeding than an exotic lawn. It self-seeds to thicken its own cover, which is what you want in a lawn, and stays where it is sown rather than escaping.
John Tann from Sydney, Australia, CC BY 2.0, via Wikimedia Commons
Where it works
The native lawn or meadow choice for sun to part shade in cool temperate through subtropical gardens. Mow it high for a soft lawn or leave it unmown for a meadow effect. It also blends well with other groundcovers in a mixed planting rather than a pure sward.
Scrambling climber — trained as a ground layer9. Running postman (Kennedia prostrata)
Shades out seedDry, sunny banks
Running postman is a climber grown flat rather than up, its slender trailing stems sprawling one to two metres across a bank to cover ground and shade out weed seed. It carries scarlet pea flowers through spring and, being a legume, fixes nitrogen as it grows. It is hardy, adaptable and not aggressive, dying back manageably rather than taking over.
Where it works
Dry, sunny banks and rockeries across temperate southern Australia including WA. Its more modest spread makes it a good partner to the larger prostrate grevillea, filling the smaller gaps a big groundcover shrub leaves around its edges.
Litter smothering — under a specimen tree10. Drooping she-oak (Allocasuarina verticillata)
Litter smotheringUnder a specimen tree
Drooping she-oak is a small tree whose fine needle-like branchlets drop a dense, slow-rotting litter that physically blocks weed seed from germinating beneath the canopy. Research on she-oaks finds this suppression is mostly a physical smothering effect, with a smaller chemical contribution, which is why bare ground tends to persist underneath.
Drooping she-oak (Allocasuarina verticillata) — the dense needle litter beneath the canopy smothers weed seed, which is why bare ground persists under an established tree.
Where it works
As a specimen tree on dry ground in southeastern Australia, where the litter zone beneath it stays naturally clear. For warmer and subtropical zones, Casuarina species give the same litter effect.
Planting and maintaining the site
Plant in combinations rather than relying on one species. A prostrate grevillea underplanted at its edges with running postman, or mat rush drifts with kidney weed filling between them, closes over faster and leaves fewer gaps than any single plant on its own. The layered planting approach applies at ground level just as it does higher up.
It takes a season or two of establishment and some patience with the first year's weeding, but the result is a garden that suppresses its own weeds permanently rather than one you fight every spring.
Through that establishment period, the table below sets out what weeding each stage needs and the tool that suits it.
Clear all existing weeds and roots before planting
Remove weed seedlings between young plants before they establish
Lift taprooted weeds whole so they do not reshoot
Top up mulch on bare soil between establishing plants
When
At planting and again mid-season
Tool
Coarse bark or leaf-litter mulch, by hand
Spot-weed gaps before the planting closes over
Pull back groundcover runners from paths and edges
Weeding between young plants through the first season is the work that gets a planting to the point where it suppresses its own weeds.
Letting the garden do the work
A well-chosen planting of ground-covering natives turns weed control from a recurring chore into something the garden handles on its own. The bare soil that weeds depend on simply stops existing.
The same plants that exclude the weeds also have the added benefit of feeding nectar-eating birds, sheltering insects and holding moisture in your soil.
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A Guide to Australian Native Gardening
How to plan, plant and care for a thriving native garden, whatever your experience level.
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