Making sure NZ does not lose critical information on weeds species is one of the key drivers for the researchers behind a recent project partly funded by the T.R. Ellett Agricultural Research Trust.
Senior scientists Trevor James and Paul Champion are deeply passionate about supporting the wider community understand the weeds species we have here in New Zealand. Their original book titled ‘Common Weeds of New Zealand’ was first produced in 1998 and has since had two updates and sold more than 15,000 copies in total. The book has been used by farmers, growers, agronomists, seed importers, students and the general public. Funding from the Ellett Trust is allowing a 4th edition to be produced and given the last edition is now 15 years old, there is a lot that needs updating. This includes research, identification, write up and photography of the new weeds for the new edition.
Some weed species have spread to whole new areas of NZ, hence the requirement to update the book. This kind of in-depth information is not readily available currently and with weeds exploding in the past 10 years (with at least 20 new readily identifiable species having come across the border), this information is critical. It will be used as a kind of ‘early warning system’ for farmers to keep an eye out for these plants.
There are many contributors to the book including councils, other organisations, independent specialists and members of the public. Many enthusiasts upload photos to an online database (iNaturalist) allowing the research team to take a look and consider what new species should be included in the book.
“We are not producing this book in isolation, we are working with many others including some who utilise online, digital platforms” explains Trevor, Principal Scientist of the Forage Science Team in AgResearch, based at the Ruakura Research site near Hamilton. “We also steer readers to various websites like Weedbusters that have specific weed management techniques so that they are seeing the very latest information in eradication and/or control”.
Trevor, whose collection of photos is currently upwards of 60,000, is taking most of the photos for the updated book. They expect to end up with around 850 species identified in the book.
One key consideration when undertaking this huge project was to ensure there was capability building of staff within research institutes to ensure that others can take up the mantle. With over 90 years experience between the two of them, Trevor and Paul, who has recently retired but was a Principal Scientist, Freshwater Ecology, at NIWA in Hamilton for many years, are very mindful that they need to pass on their knowledge to others with interest in this area.
“Weed scientists are somewhat of a dying breed and we want to ensure we are leaving a legacy for future generations” notes Trevor.
Zachary Ngow, a research associate at AgResearch, and Murray Dawson, a botanist at Landcare Research, are supporting the work with Trevor and Paul. Zachary is focusing on ferns and bamboo and Murray is already a co-author of weed identification keys online so is incredibly helpful in updating the book.
“The funding from the Ellett Trust has meant we have the resources to be able to interact with more people. This has given us the freedom to spend a decent amount of time on this, otherwise it would have been a labor of love and taken longer to the get the information into the hands of those that need it” states Trevor.
This work is done for the betterment of the wider community with its impacts far-reaching, not just for farmers but the industry as a whole. The information supports the Ministry for Primary Industry’s ‘National Plant Pest Accord’ and Regional Pest Management Plans produced by each regional council. The funding has enabled both the support the publishing of the next edition of the book as well as online publications too. It investigates environmental weeds for the likes of parks and reserves as well, helping the wider community, particularly the work that the councils are doing around the country.
Following publication of the latest edition of ‘Common Weeds of New Zealand’ due in early 2026 an updated sister publication titled ‘Common Guide to Grasses, Sedges and Rushes of NZ’ will be published in 2027.