About weeds

[Clematis vitalba] (old mans beard). Image: © Murray Dawson

Sadly, the number of weeds (naturalised species that include pest plants) is now greater than our native flora. Weed species out-compete and displace our native flora and fauna, reducing biodiversity of New Zealand’s unique ecosystems. Weeds cost New Zealand’s economy billions of dollars annually through lost productivity and control measures. For example, pastoral weeds cost more than $1 b annually in control measures and lost productivity.

Pest Plant Officers, Regional Councils, DOC, and landowners involved in the control of pest plants desperately need more community support. They need trained eyes, and boots on the ground, from informed communities of observers to help discover pest plant infestations. Early intervention is the most cost-effective way to manage weed infestations, but this is reliant on their timely detection, identification and reporting. International studies have found that once a weed infestation covers more than 1 ha the likelihood of successful eradication is poor at around 33%.

To win the war against weeds perceptions need to change, driven-by the next generation of informed enviro-kids who are better connected with nature. Wildflower weeds marching along roadsides and self-seeding conifers overtaking open landscapes may look attractive to the uninformed, but from environmental and economic viewpoints they are disastrous.

Plantings in school grounds, parks, marae, and people’s gardens contain numerous National Pest Plant Accord (NPPA) species prohibited from sale, propagation, distribution and display because of their weedy qualities. But how many of us know about these banned species? Every year, plants in cultivation ‘jump the garden fence’ and escape into the surrounding environment.

Together, we can do better. This project will work with whanau and enviro-schools to discover which weeds are found in problematic, under-collected, and widely separated areas in New Zealand.

This project will also improve the awareness and understanding of natural biological control options, what these are, how they work, and the benefits they provide.