Push to declare garden favourite sold at Bunnings a weed

Polygala, a popular purple flower sold in Australia under names like sweet pea, Bellerine pea, and parrot bush, is causing significant environmental harm along the country's coastline. Despite being stocked in major retail stores, including Bunnings, the Invasive Species Council has named Polygala myrtifolia as one of Australia's most significant weeds. This shrub, originally from southern Africa, outcompetes native plants, transforms habitats, and deprives wildlife of essential resources.

Dr. Carol Booth, policy director at the Invasive Species Council, emphasizes the dense shrub layer formed by Polygala, which excludes native flora and negatively impacts the environment. The council has targeted Bunnings for stocking gazania seeds, which are banned in South Australia and recognized as environmental weeds in several other states. However, Bunnings continues to sell hybrid polygala, which differs from the invasive species.

Australia has a government-endorsed list of 32 Weeds of National Significance (WONS), but Dr. Booth argues that the list needs updating to include milkwort and other invasive plant varieties. With about 3,000 introduced plant species naturalized in Australia, roughly one in nine species growing in the wild is non-native. More than 1,000 of these are considered invasive, causing harm to native species and ecosystems.

The polygala's popularity among suburban gardeners, due to its hardiness and ability to thrive in harsh conditions, also makes it challenging to eradicate once established.

Controlling the invasive bush involves either herbicides, which are expensive and may harm native flora, or manual removal, which is labor-intensive and time-consuming. The Invasive Species Council and Nepean Peninsula Landcare are exploring a potential biological control method to combat the weed.