As Australians, we have a deep-seated love for our gardens. They’re our personal patches of paradise, where we can cultivate beauty and tranquility.
The tradition of cultivating gardens holds a significant place in the Australian way of life. Gardens provide spaces for both aesthetic enjoyment and personal satisfaction.
However, within the realm of horticulture, there exists a potential challenge that warrants careful consideration regarding its broader environmental implications.
Relevant authorities have raised concerns regarding certain plant species commonly available for purchase.
Lurking among the rows of vibrant flowers and lush foliage at your local garden store could be a hidden menace—plants that, while seemingly harmless, have the potential to become Australia’s next invasive weeds.
The Invasive Species Council (ISC) has raised a red flag over the tens of thousands of plant species available for sale in nurseries across the country.
Alarmingly, fewer than a quarter of these plants have been assessed for their invasive potential. This oversight could lead to ecological disasters, as unassuming garden plants escape into the wild and wreak havoc on native ecosystems.
The issue came to the forefront when Bunnings, a retail giant, was reportedly found selling gazania—a flowering plant native to southern Africa that has been declared a weed in several Australian states.
This is just the tip of the iceberg, according to ISC national strategy lead Imogen Ebsworth, who warns of the ‘terrifying known unknowns’ that gardeners might unwittingly introduce into the environment.
‘Part of the difficulty is we know there are more than 30,000 different plant species available for sale for your garden in Australia and we also know the vast majority of them haven’t been assessed for whether they’re going to turn into a major weed’
The statistics are sobering: a 2004 report by biosecurity strategist John Virtue found that at least three-quarters of established weeds in Australia originated from garden escapes.
In the past year alone, the ISC has identified several plants for sale in nurseries, such as mother-in-law’s tongue, mock orange, Japanese honeysuckle, duranta, and English ivy among others, which are known weeds in other parts of the world.
Professor Singarayer Florentine from Federation University, an expert in invasive species and restoration ecology, points out that the very traits that make these plants attractive to nurseries—their hardiness and low water needs—also make them formidable weeds.
Gardeners seeking ‘easy fix’ options may inadvertently contribute to the spread of these plants, like agapanthus, which can propagate through tubers even if their seeds are inert.
‘There are varieties of agapanthus with sterile seeds but they can spread by their tubers, which are capable of producing multiple plants,’ the professor said.
The sale and spread of potential weeds are exacerbated by a lack of regulation and poor coordination between state governments.
It’s possible to purchase plants that are declared noxious weeds in some parts of Australia but not in others, leading to what Ms Ebsworth describes as a ‘hot mess’.
‘You can definitely walk into Bunnings or another major nursery and grab handfuls of plants that are declared noxious weeds in some parts of the country, but not in others.’
The Centre for Invasive Species Solutions (CISS) works to assess the invasiveness of plant species and recommend whether they should be declared noxious weeds.
This process is based on scientific evidence and considers factors such as the plant’s rate of spread, impact on native species, and risks to agriculture or infrastructure.
Despite the national weeds strategy being introduced in 1997, it wasn’t until 2024 that a specific action plan to address escaped garden plants was agreed upon.
This plan is crucial, as it aims to assess the thousands of plants in Australia, identify known and potential weeds, and then ban and restrict their sale.
It also seeks to identify ‘sleeper weeds’—plants that may have only begun to establish locally but have the potential to spread widely.
Time is of the essence, and gardeners play a critical role in preventing the spread of invasive species. Before you add that next plant to your cart, consider its origins and potential to become a weed.
Research the species, consult with local experts, and choose native or non-invasive plants whenever possible. By doing so, you’ll not only protect your own garden but also contribute to the preservation of Australia’s unique and precious ecosystems.
We urge our readers to be vigilant and informed gardeners. Have you ever encountered an invasive plant in your garden? What steps do you take to ensure your green thumb doesn’t turn into an ecological nightmare?
Also read: Some people are getting this garden item for free ahead of autumn
