Polygala myrtifolia, a beauty and a beast!

Polygala myrtifolia, a beauty and a beast!

Update July 2026:

How beastly is this little beauty?

More locally on the Tomaree Peninsula – the myrtle-leaf milkwort, Polygala myrtifolia, seems to have been planted in Nelson Head’s gardens. It’s prevalent throughout Shoal Bay’s coastal dune, particularly the western strip from Nelson Head to the neighbouring Anzac Park. In Tomaree Lodge’s bushland it was prevalent, but thankfully in 2025 the process of removal commenced which will require ongoing annual maintenance.

It has a long history in Tomaree National Park – possibly emanating from Tomaree Lodge, it is on Tomaree Headland and Zenith Beach, and has reached Wreck and Box beaches. For us, in the Friends of Tomaree National Park, our association with Polygala goes back to our beginnings – our first workbee in October 2020.

At Tomaree’s Zenith Beach – we sighted an unfamiliar pea plant. Fortunately one of our team members, Barb, in our newly established team had seen National Parks and Wildlife Service rangers working elsewhere on what looked like this pea and alerted us to its potential as a problem plant.

This became our priority task in these early days at Zenith Beach, as it was flowering when we started and easily seen — a great task for a new group learning the ropes!

We’ve removed the numerous Polygala on the windward side of the frontal dune, and scattered between the bushes on the ridge and down the dune’s leeward side. And we’ll keep maintaining this area. We are finding it to be a task harder than managing bitou bush – with its seemingly more persistent seed stock in the ground.

Since 2020, as well as Zenith Beach, we have been removing Polygala on Tomaree summit, Wreck Beach and Box Beach.

Managing Polygala myrtifolia is a constant for at least 5 years at each site

Birds, ants, water, soil movement and garden refuse can disperse Polygala seeds, which remain viable in the soil for up to 5 years, maybe longer.

Seedlings grow quickly, flowering when less than 50 cm tall. It grows mainly over the cooler and wetter winter and spring periods. One reference indicates time to first flowering is 3 years (WA), though we feel it’s been faster in our wet weather these recent years, and we work on about 12-18 month cycles to check. Seedlings thrive in shade – so we’re extra vigilant looking under bushes in areas where Polygala occurred.

The mature plant flowers mainly in spring to summer to produce seed for an autumn germination. High levels of seed production and seed dormancy results in significant soil seed banks.

Cut rather than pull! Seedlings are hand pulled. Larger plants can be often be hand pulled, but are better cut at the base from which they rarely regrow. This creates less soil disturbance and less seed germination than pulling the larger plants. If you’d like to find out more about seed germination and its implications, this research abstract is a good summary.

In the national park, Polygala is seemingly only in the northern end

We started working on Polygala at Zenith Beach, and fortunately it was almost restricted to the centre block between the two access paths to the beach. Concurrently we also managed bitou.

Since late 2020 when we started, we’ve had annual checking cycles and hopefully none have seeded in that time. However we have found flowering Polygala where we missed young plants on earlier checks and a missed patch of adults, not located until 2024.

We’ve since managed Polygala on Tomaree summit starting 2021, and believe in those years none have seeded above the yellow brick path to the bitumen path of the gun emplacements. Below that area we are gradually bringing Polygala under control. However Polygala (and bitou) around Tomaree Lodge is a constant source of recruitment into the national park until it can be controlled also, fortunately that started in 2025. There are sites only accessible to climbers where it is proliferating and some climbers do remove on their recreational climbs.

Our priority is to maintain the areas already managed and try to ensure no new plants grow to seed again, rather than spreading ourselves too thinly over too many sites. We are steadily removing Polygala across Tomaree NP.

Polygala’s look-a-likes: several plants in Tomaree look similar.

In flower there’s little to confuse with Polygala  – though some have suggested the threatened mint bush Prostanthera densa in flower could be confusing to the novice. 

However seedlings are easily confused. Seedlings of Coast Teatree, Leptospermum laevigatum, the native Coast Beardheath, Leucopogon parviflorus, and the pea Pultenaea daphnoides also look similar to Polygala seedlings. We allow Polygala seedlings to grow sufficiently for us to confidently distinguish from native seedlings.

Possibly the strongest look-a-like is Shrubby Platysace (Platysace lanceolata). While their flowers are distinctive (Platysace has tiny white flowers packed in a cluster, September to March), and when maturing, Platysace is a more spreading shrub while Polygala is more upright. However FoTNP are mostly looking at leaves to distinguish younger plants so this is a challenge.

Tomaree Head is the only place FoTNP have found both species in overlapping areas. As well as Tomaree Head, Polygala’s been located at Zenith, Wreck and Box beaches. FoTNP so far have found Shrubby Platysace at Tomaree Head, Fingal Beach north in the forest, and further south in the national park. Native Shrubby Platysace is likely widespread in the park, so care is needed not to confuse the two.

Polygala is banned in New Zealand ~ why not Australia? 

With so many coastal ecosystems under threat from urbanisation, stopping new sources of potential weed invasion, such as from plant sales, should be a high priority. Polygala can thrive inland also, so a ban on Polygala sales has the potential to minimise new invasive sources across a broad spectrum of Australia’s landscape. 

CSIRO research concluded: “There is high risk of P. myrtifolia further invading sensitive ecosystems because of its high germination success. Preventing seed dispersal and ensuring seedlings are controlled on emergence are critical to reducing its impact. We recommend that the cultivation and sale of this species should be prohibited across Australia to prevent further spread.”

Polygala is banned in New Zealand, so why is this not happening in Australia too?

If you or neighbours grow Polygala myrtifolia then …

Consult Grow me instead to find an alternative native plant, though best if the alternative is a local native from your area. There are so many beautiful hardy local Tomaree shrubs there’s really no need to grow Polygala.

Other flowering shrub alternatives that are readily available

• Coastal Rosemary (Westringia fruticosa): Matches Polygala’s dense, rounded structure and salt tolerance, providing white flowers year-round. 
• Thyme Honey-myrtle (Melaleuca thymifolia): A smaller local native shrub thriving in local heathlands, featuring delicate pinkish-purple blossoms.
• Native Fuchsia (Correa reflexa): A hardy understorey shrub with beautiful bell-shaped flowers that attract nectar-feeding birds.
• Coastal Tea Tree (Leptospermum laevigatum): A tough, larger shrub excellent for windbreaks and dune stability, producing mass white flowers in spring.
• Native Mint Bush (Prostanthera species): Offers a direct aesthetic swap, blooming with vibrant purple flowers that support local native pollinators. the native species in Tomaree is endangered and not readily available but other NSW native species are not invasive and better than Polygala myrtifolia

And there’s two native Polygala species in NSW, though not in Tomaree Peninsula

The Dwarf Milkwort Polygala japonica is largely in grasslands and grassy understory of open forests along eastern NSW, and the threatened Polygala linariifolia is found in north eastern NSW.

And there’s additional Polygala weed species, Polygala paniculata and Polygala virgata.

Tit bits of info – fact or fancy? 

• Name comes from the Greek “Polus” meaning much and “Gala” meaning milk and refers to the ancient belief that animals eating these plants produce more milk. The species name myrtifolia means myrtle-like leaves.
• In its native South African habitat, it’s described as a pioneer species — readily establishing in disturbed areas hence its invasive nature here. 

Further reading

PolyGone Project investigating environmental biocontrols

Weeds Australia Polygala myrtifolia January 2024