Asian weed sneaks into New Zealand through bagged coco peat
Invasive Species
If you've ever topped up a planter with bagged coco peat or coir, you may have unknowingly introduced a new weed species along with it.
Researchers found a small yellow-flowered plant called Youngia japonica growing wild in five spots around Auckland and Northland, New Zealand, the first time it's ever been recorded there. DNA testing confirmed the plant's identity, and the scientists suspect it hitched a ride in imported coco peat, the fibrous growing medium popular in potting mixes and garden beds. It's a reminder that the soil amendments we bring into our gardens can carry unwanted stowaways.
Key Findings
Five populations of Youngia japonica subsp. japonica confirmed across Tāmaki Makaurau/Auckland and Te Tai Tokerau/Northland, marking the species' first verified record in New Zealand.
Identification was confirmed using both morphology and DNA sequencing (nrDNA ITS1/ITS2 and chloroplast trnH-psbA regions).
The discovery extends the species' known range into the southwestern Pacific and adds to evidence that imported coco peat is a vector for new weeds entering the country.
chevron_right Technical Summary
Scientists confirmed that an Asian weed called Youngia japonica has established itself in New Zealand for the first time, likely arriving hidden in imported coco peat growing medium used by gardeners and nurseries.
Abstract Preview
Original paper
First record of Youngia japonica (L.) DC. (Asteraceae: Tribe Cichorieae) in Aotearoa / New Zealand
We report the first verified records of Youngia japonica subsp. japonica (Asteraceae: Tribe Cichorieae) in northern Aotearoa / New Zealand. Five populations have been discovered across Tāmaki Makau...
open_in_new Read full abstractAbstract copyright held by the original publisher.
Species Mentioned
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Youngia japonica, commonly called Oriental false hawksbeard, is a species of flowering plant in the family Asteraceae. Native to eastern Asia, it is now found as a weed nearly worldwide.