16 October 2007

Nasty weeds exposed during dirty weekend in Wellington

The offer of “a dirty weekend in their own back yard” appealed to Wellington and Kapiti gardeners who swapped their weeds for more than 900 native plants at weed swaps last weekend (October 13 and 14)

Weed experts from the Department of Conservation and Greater Wellington Regional Council identified 122 species of pest plants, including the unpleasant Madeira vine, a tropical South American perennial creeper that grows to 20 metres, seriously threatening our native vegetation. Limited to just a few sites in the Wellington region it can be eradicated with help from the public.

A specimen was brought into the weed swap at Wellington’s Waitangi Park by unsuspecting Thorndon resident Laura Woodward who found it growing in Tinakori Road. She became an instant hero, receiving prizes as well as free native plants.

“It’s a very exciting find,” said Greater Wellington Regional Council biosecurity officer Pedro Jensen. “We can now go out and kill it.

It’s the second Madiera vine infestation uncovered at weed swaps held by DOC, in conjunction with Greater Wellington and local councils over the past two years. An infestation at Taita was revealed at a weed swap in Lower Hutt in August last year.

Despite its alluring name and fragrant flowers, chocolate vine was the worst weed brought into the Kapiti weed swap, part of the Sustainability Expo at Kapiti Uniting Church.

Prohibited from propagation, sale and distribution within New Zealand, this fast-growing twining vine, native to central China, Korea and Japan, has naturalised in New Zealand and been found climbing over indigenous shrubs. Its dense growth prevents seed germination and seedling establishment of native plants.

It has recently been added to the National Pest Plant Accord and is one Greater Wellington’s surveillance species. There are about 50 known sites in the Wairarapa and 10 in Kapiti.

“We suspect there are a lot more sites so would be interested in any more reports,” says Greater Wellington biosecurity officer (pest plants) Mike Urlich.

People who thought they had uncovered a lethal weapon in their gardens discovered that their offerings of nightshade were of the velvety and black variety, not the more poisonous deadly nightshade which is rare in New Zealand

Wandering willie - a trailing plant that forms dense mats that smother native plants - was the most prevalent of the weeds delivered to both weed swaps. Sixteen specimens handed in at the Waitangi Park event and 27 at Kapiti

Veldt grass was runner up in Wellington (12 specimens) with puha in second place at Raumati (18 specimens)

Onion weed, wild turnip, fleabane, scrambling fumitory, chickweed, bindweed, red dead nettle, black nightshade and dandelion were also among the top 10 weeds at the Wellington event. Kapiti’s top 10 included scrambling fumitory, velvety nightshade, hawkbit, velt grass, chickweed, cleavers, periwinkle, and fleabane.

Both events were well supported with a diverse range of weeds presented,” says DOC weed ecologist Clayson Howell.

“Most were typical back-yard weeds, such as wandering willie, but it was great to see a range of woody weeds too, and lots of serious weeds such as Darwin's barberry, climbing asparagus, and Franchet's cotoneaster.”

The weeds were swapped for such native species as cabbage tree, rengarenga lily, wineberry, toetoe, flax, carex species, and lemonwood, courtesy of DOC. Around 500 were handed out at the Wellington event and 400 at Kapiti.

Report pest plants to the Greater Wellington Regional Council pest plants office, Phone: 04 526 4133
Identifying weeds:
Pick up Plant me instead – a guide to environmentally-friendly gardening (available from garden centres and bookshops) or visit the following websites:
Weedbusters: www.weedbusters.org.nz
Greater Wellington Regional Council: www.gw.govt.nz
New Zealand Plant Conservation Network: www.nzpcn.org.nz

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