Join our Great Willowherb Hunt

We’re calling on Waitaha Canterbury residents to take part in the Great Willowherb Hunt — a summer campaign to track down one of the region’s most aggressive wetland invaders.

Anyone who reports a sighting between now and 28 February will go in the draw to win one of ten $100 Prezzy cards, adding an extra incentive to keep eyes peeled while out exploring.

Quick facts about great willowherb

• Great willowherb (Epilobium hirsutum) is spreading rapidly across Canterbury’s wetlands and waterways.
• First found here in 2018, and Canterbury is still the only place in New Zealand where it’s known to occur.
• The tall, hairy-stemmed plant can reach two metres in height and is easily recognised in summer and autumn by its bright pink‑purple flowers.
• Forms dense stands that overwhelm native wetland plants, alter waterflow, and disrupt habitat for birds and invertebrates.

Our wetlands are among the region’s most valuable ecosystems, and early detection of invasive species like great willowherb is crucial for effective management. With thousands of people tramping, hunting, biking, and exploring waterways at this time of year, we’re asking the community to help us map where this plant is taking hold.

How to join the hunt

Taking part is simple:

• Spot it – Look for tall, pink-flowering stems with lance-shaped leaves.
• Snap it – Take a clear photo showing the plant and its features.
• Record the location – Use your phone to drop a pin or note coordinates.
• Report it – Upload your sighting to our iNaturalist project or submit it at reportpests.nz.

Every report helps us build a clearer picture of where great willowherb is spreading and how we can respond.

We encourage everyone enjoying the outdoors this summer to get involved. Every sighting helps protect the wetlands and waterways that make Canterbury unique.