News | 19 October 2021
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Team spirit stopping weeds dead in their tracks

It’s amazing what a difference people can make when they work as a team – especially when it comes to conservation.

A young woman with dark hair tied in a pony tail, wearing blue and orange work overalls, kneeling on a hillside planting a small tree, surrounded in bush.
Kaitiaki o Ngahere team member Jess with juvenile bomarea.

Wellington City Council staff, the crew at Kaitiaki o Ngahere, and groups of community volunteers have been working together to restore Polhill/Waimapihi Reserve. Their mahi is crucial to the future of the reserve – especially when it comes to controlling weeds. 

Wellington City Council Biosecurity Specialist Illona Keenan says the main goal is to protect diversity in our reserves.

"As humans we've introduced so many invasive plant species to New Zealand. We need to do whatever we can to control these invasive plants and stop them from destroying our native forests and reserves.”  

At Polhill/Waimapihi Reserve, Kaitiaki o Ngahere focuses on controlling five main weed species: bomarea, old man’s beard, climbing asparagus, Japanese honeysuckle, and banana passionfruit. These nasty plants suffocate native plants and trees, spread quickly and are incredibly difficult to control.  

Described as a ticking time bomb, bomarea is the most aggressive weed in the reserve. Bomarea is a fast-growing, scrambling vine that forms large masses and can smother and kill supporting trees. Shade tolerant, it also strangles saplings and smothers low growing native species, and its seeds are spread by birds.

Bomarea grows a couple of feet in its first year. In summer it has red/orange tubular flowers that hang in clusters of 15-20 flowers. Then, in its second year, it creates seeds that can be spread by birds up to 100 metres away. 

Kaitiaki o Ngahere is committed to the conservation and restoration of New Zealand’s natural areas through the provision of innovative specialist consulting and operational services, Branch Manager Stu Whiterod says.

“We are working with Wellington City Council to control bomarea, old man’s beard and other ecologically damaging weeds from the reserve and to stop them spreading.” 

A man wearing glasses, gloves, and a high-vis orange vest, handling leaves of a flowering mature bomarea plant in the bush with tall trees behind him.
Kaitiaki o Ngahere Branch Manager Stu Whiterod with flowering mature bomarea.

Community volunteer groups such as Brooklyn Trailbuilders, and the Polhill Protectors/Ngā Kaimanaaki o te Waimapihi, work alongside Kaitiaki o Ngahere and the staff at Wellington City Council to control other invasive species including old man’s beard and blackberry.


They work on the ground digging out the roots of these harmful plants, removing flowers and seed pods, using herbicide gel to kill the root systems and stop the plants from spreading.


Jim Mitford-Taylor works with Kaitiaki o Ngahere during the week and his evenings and weekends are spent coordinating the Ngā Kaimanaaki o te Waimapihi/Polhill Protectors. 

I believe that collaborating with passionate local kaimanaaki to protect our native forests is the most rewarding thing you can do with your spare time."

This conservation work is so crucial to Polhill/Waimapihi Reserve. It neighbours Zealandia and has an increasing number of bird species jumping the fence including hihi, tieke, toutouwai and popokotea. It’s also one of the only places in New Zealand to have tree fuchsia (the largest fuchsia in the world).

Thanks to these people coming together to destroy invasive plants, the reserve has a positive future and will continue to be protected. 

Are you keen to help stop the spread of weeds?