Lomatia fraseri, an Australian tree newly weedy in New Zealand

Lomatia fraseri, an Australian tree newly weedy in New Zealand

Invasive species are one of the biggest threats to indigenous biodiversity. Another new weed for Aotearoa New Zealand has been reported by Botany Curator Leon Perrie and Geneticist Lara Shepherd. They ask whether we are doing enough to identify and control new weeds.

Weed species – exotic plants that have been recorded as self-propagating – now outnumber indigenous species in Aotearoa New Zealand among vascular plants (principally flowering plants, conifers, and ferns). Indeed, New Zealand’s North and South Islands are some of the weediest islands in the world. And the list of weeds continues to grow at a frightening rate.

Our recent publication in Te Papa’s journal Tuhinga adds another weed for Aotearoa New Zealand, documenting the establishment of the Australian tree Lomatia fraseri.

Our paper is freely accessible here.

A bushy small-leaved tree surrounded by other trees.
Lomatia fraseri is a small tree indigenous to New South Wales and Victoria in Australia. It is in the Proteaceae family. Photo by Leon Perrie

Lomatia fraseri in New Zealand

A ridge overlooking Wainuiomata is infested with thousands of individuals of Lomatia fraseri. This was first brought to our attention in July 2019. But it is clear that Lomatia fraseri has been establishing at this site for much longer, given that there are many individuals and some of them are big.

Self-sown individuals have also been reported from elsewhere in the Wellington region and near Christchurch.

Small hedges and trees along the side of a dirt road
Adults, saplings, and seedlings of Lomatia fraseri lining a track through mānuka forest on a Wainuiomata ridge. The infestation is very dense in places and extends over 2 km. Seedlings have been found about 2 km away. Photo by Leon Perrie
Bushy small-leaved trees surrounded by other bush.
Lots of saplings and seedlings of Lomatia fraseri. Photo by Leon Perrie
A close-up view of seedpods on a branch
Lomatia fraseri disperses by wind-borne winged seeds produced within black, somewhat woody fruits. These seeds are similar to those of related Hakea species that have become widespread environmental weeds in some parts of Aotearoa. The scale bar in the inset is 1 cm. Photos by Leon Perrie

Lomatia fraseri has a fairly wide indigenous distribution in mainland Australia. This indicates it can thrive across different environments.

In Aotearoa New Zealand, Lomatia fraseri has demonstrated its ability to both dominate suitable sites and disperse reasonable distances.

Nevertheless, weed management authorities are not controlling the Wainuiomata infestation because it is not in a so-called “Key Native Ecosystem”. KNEs are those that are “the best and most threatened examples of our native ecosystems”. However, several KNEs are within only 4 kilometres.

It might turn out that Lomatia fraseri is largely restricted to regenerating mānuka forest. Even disregarding the natural values of mānuka forest, there is the potential for Lomatia fraseri to impede what is now a lucrative honey industry.

What you can do

Adults and saplings of Lomatia fraseri are very distinctive. If you see plants outside cultivation, please report them to your local council, and record them in the public domain with the likes of the iNaturalist website. Leave a comment below if you’d like me to help with identification.

Additionally, given that Aotearoa New Zealand’s indigenous species and ecosystems are being overrun by weeds, you might like to ask your local council to do more.

You can learn how to recognise and control the worst of our weeds on the excellent Weedbuster’s website.

How many weeds are on your whenua (land)?

Pointy-leaved branches of a small tree.
Lomatia fraseri has long, narrow, and toothed leaves. Photo by Leon Perrie
White flowers on the end of a branch
The summer sprays of white flowers of Lomatia fraseri are distinctive among the New Zealand flora. Photo by Leon Perrie
A close-up of white flowers on a spiky-leaved tree
Close-up of the flowers of Lomatia fraseri. Photo by Leon Perrie
Open seed pods on the ends of branches surrounded by bush
Adults of Lomatia fraseri hang on to their black follicle fruits throughout the year, which is another distinctive character among the New Zealand flora. In this photo, the follicles have opened and shed their seeds, revealing their paler, brown insides. Photo by Leon Perrie
Young leaves on a branch
Juvenile plants of Lomatia fraseri occasionally have lobed leaves. Photo by Leon Perrie
Small spiky leaves on the ground
Seedlings of Lomatia fraseri (left of centre) are similar to those of the indigenous rewarewa, Knightia excelsa (below-right of centre), which is also in the Proteaceae family. However, the leaves of rewarewa seedlings are narrower, have more and smaller teeth, are usually yellower, and have a darker midrib. Photo by Leon Perrie

The bigger picture

It’s concerning that such a distinctive weed has been able to establish so intensively and for so long within a major suburb of Aotearoa New Zealand’s capital city. Is the country doing enough to spot newly establishing weeds and pests?

Furthermore, even when we are spotting new weeds and pests, is enough being done to stop them? Lomatia fraseri has already shown it can invade and spread.

As we write in our paper, “We fear that by leaving yet another exotic species to establish itself in New Zealand, we (the New Zealand of 2021) will be shown to have been negligent in our kaitiakitanga (caretaking) of the taonga (treasures) that are the indigenous plants, animals, fungi and other biota of Aotearoa.”

Further reading

5 Comments


  1. A native we don’t like? Like spur-winged plovers.

    A wind-blown native we like? Orchids.

    1. Author

      Kia ora Robert.
      Lomatia fraseri is native to mainland Australia. It is not native to New Zealand. But it has been introduced to New Zealand and cultivated here, presumably as an ornamental.
      It’s estimated that some 20000-30000 exotic plant species are cultivated in New Zealand (compared with c. 2500 native vascular plant species). Exotic plants originally cultivated in New Zealand are steadily becoming naturalised (i.e., going weedy) here – Lomatia fraseri is another one of these.
      Ngā mihi, Leon

  2. A large part of the problem is, I think, that there is a very limited number of people who have an interest in and knowledge of weed species. This means that early and potentially controllable infestations are missed with the result that large sums of money are spent on well established infestations. Such efforts are often futile. There is no easy solution.

    1. Author

      Kia ora Mike,
      I agree about the lack of interest/knowledge. Which is why MPI’s strategy of relying on public surveillance seems ambitious/misguided. The solutions aren’t easy, but maybe involve greater active surveillance by biosecurity agencies and greater education for the public about identifying/recognising biodiversity. As you know, iNaturalist can play a part in both of these, but maybe more so the latter.
      Kind regards, Leon

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