Making weeds part of the solution

Wild Ginger, Tradescantia, Convolvulus – words to make any gardener shudder. But what if the problem could be part of the solution?

Students from Henderson Valley Primary School show just how much the giant weed bags can hold.

The Weedfree Waitakere Trust is trialing a scheme that could turn problem weeds into rich compost instead of landfill waste.

Community Projects  Co-ordinator Neil Henderson says “Many tough weeds removed from gardens can’t be composted in the usual way because they survive the process and live to reinfest new ground. Instead, they have to be buried like nuclear waste deep in landfills along with household rubbish.”

The Weedfree Waitakere Trust’s latest  brain-child is a giant bag made of light-proof weed matting that can be stuffed full of weeds which are then left to rot. The process might take a year or more, but in the end eco-battlers are left with rich compost that can be used to feed the saplings they’ve planted to replace the weeds.

“The beauty of it is that people can drag something like Tradescantia (Wandering willy),a plant that doesn’t set seed, down a steep hillside, stuff it in our black bag and leave it there. They don’t have to haul it long distances to bins or trailers, which only encourages it to spread further because every segment that breaks off can regenerate.”

Neil is always looking for novel approaches to the weed problem and he says creative land owners are always coming up with promising alternatives to the traditional spray and slash approach.

One Waitakere resident has developed a technique that can kill the notoriously tough Wild Ginger’s root system in a month. The roots are crammed into a large barrel, covered with water and then concentrated natural enzymes and microorganisms are added.

“It’s a bit like making sour dough bread, taking a few scoops from the rotting mixture and transferring it to the fresh barrel. After a month, you can tip them out and let them rot. They won’t grow back. It certainly saves a trip to the dump.”

The Trust also works with school groups throughout the Waitakere City area, educating students about problem weeds and how to eradicate them. Although it is an independent charitable Trust, the Weedfree Waitakere Trust works closely with the Local and Regional Councils, helping landowners develop management plans to win the weed war.

“You’ve got to start small, but do it well,” Neil says. “Whatever you start, it’s got to be sustainable, otherwise you’ll get rapid reinfestation and this can be expensive and discouraging.”

In an area rich in natural vegetation, he also advises landowners to work with the land. “It’s important to let the bush be bush; otherwise you’ve always got to put in a huge effort.”

For more information, visit www.weedfree.org.nz or phone 826 4276.

This year ASB Community Trust granted the Weedfree Waitakere Trust $30,000 toward its operating costs.