Invasive garden plants in Australia you might not know about
In nature, plants exist inside tightly balanced systems. Nothing operates without influence and very little is left unchecked. When exotic plants escape our gardens, the controls that would normally limit their behaviour are often absent.
This is how many invasive plants began in Australia. While awareness has improved, older plantings remain and continue to cause problems. These plants are now in the wrong place, doing what they evolved to do in their local habitat, only without limits.
Five invasive plants often overlooked
1. Bridal creeper (Asparagus asparagoides)
Forest & Kim Starr, CC BY 3.0 US, via Wikimedia Commons
Bridal creeper was introduced as a groundcover and florist plant. It is now widespread across southern Australia and parts of Western Australia, where it has invaded bushland and coastal reserves.
Removing it from your garden
Bridal creeper has fine, glossy stems that thread through other plants and across the ground. Beneath the surface, it forms dense mats of tubers that store energy and allow it to persist through extremes. Birds spread its berries which fuels larger infestations.
Removal is slow and plants must be dug out completely, as small fragments can reshoot months later. A sharp spade, garden fork and hori hori knife are needed to work carefully through the soil. Sturdy gloves should be worn for digging and pulling, especially in compacted ground.
2. Madeira vine (Anredera cordifolia)
Madeira vine was introduced as a garden screening plant. It is now established across eastern Australia and parts of Western Australia, where it takes over bushland and waterways.
Removing it from your garden
Madeira vine has thick, fleshy leaves that smother fences and trees. It spreads aggressively through aerial and underground tubers that store energy and allow the plant to recover repeatedly. Cutting it back alone achieves very little.
Removal is labour intensive and ongoing. All top growth must be taken away and every tuber removed. Hand pruners and loppers are essential for cutting stems, followed by tough ground tools to locate and remove tubers from the soil. Sturdy gloves, long sleeves and eye protection are strongly recommended as it releases a slippery sap.
3. Mirror bush (Coprosma repens)
Mirror bush was introduced as a hardy hedging plant, particularly in coastal gardens. It is now established along much of southern Australia’s coastline, where it appears in dunes and coastal bushland.
Removing it from your garden
Mirror bush produces fleshy berries that are spread by birds, allowing it to move long distances. Once established outside gardens, it shades out low growing natives and alters coastal plant communities.
Removal is most effective while plants are still small. Seedlings and young shrubs can be dug out with a hand trowel or sharp spade. Larger plants require loppers or a pruning saw before the stump is dug out. Sturdy gloves are recommended, as the branches are stiff and abrasive.
4. Prickly pear (Opuntia species)
Prickly pear was introduced in the 1800s for fencing, food and ornamental use. It spread rapidly across eastern Australia, particularly Queensland and New South Wales, becoming one of the most severe plant invasions in the country’s history.
Removing it from your garden
This is often best left to professionals. Prickly pear consists of flattened pads that root wherever they fall. Even small fragments can establish new plants. Seeds are also spread by animals, allowing infestations to expand well beyond garden boundaries. In the absence of natural predators, it forms dense, impenetrable thickets.
Pads must be handled using tongs or thick gloves to avoid spines. Long handled tools, long sleeves and eye protection are essential. In many areas, council guidance is recommended due to the scale and persistence of infestations.
Tools for Australian Gardeners
5. Montpellier broom (Genista monspessulana)
Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons
Montpellier broom was introduced as an ornamental garden shrub and erosion control plant. It is now widespread across parts of Victoria, South Australia and Tasmania, where it can be found in bushland, roadsides and forest edges.
Removing it from your garden
Montpellier broom forms dense shrubs with fine green stems and yellow pea flowers. It produces large quantities of seed that remain viable in the soil for many years. As a nitrogen fixing plant, it also changes soil conditions, favouring its own growth while disadvantaging native species.
Removal is time consuming and often ongoing. Young plants can be pulled out, ensuring the entire root system is removed. Larger shrubs require loppers or a pruning saw before the root crown is dug out.
What keeps plants in check in the wild
In Australia’s natural systems, plant populations are regulated by multiple overlapping pressures. Insects and pathogens reduce vigour and seed set, grazing animals limit regeneration and fire removes biomass and resets growth cycles.
Introduce a single new species and a system may absorb the change, but introduce many and a small number can begin to dominate. History shows that when a plant arrives here without its natural competitors, predators or limits, there is often little to slow it down except deliberate intervention.
Why balance matters
Ecosystems are intricate by necessity. Each interaction plays a role in maintaining diversity and function. When plants sit outside those relationships, the system loses its ability to self regulate.
What does this mean for your garden? Suitability is not just about how a plant looks or performs in the short term, but how it behaves over time and what happens when it escapes the boundaries we think we are placing around it.
Recognising that highlights just how remarkable these systems are, and how easily they can be disrupted when balance is broken. Our responsibility as gardeners is to make informed choices and where possible, address the mistakes of the past.
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