Time to tackle 'one of Northland's worst weeds'

A flowering moth plant laden with immature seed pods. Photo / Supplied

People are being urged to tackle the perennial invasive moth plant as soon as possible, before its kapok-like seed pods mature and burst to infest new areas.

Jack Craw, who chairs the Northland Regional Council's Biosecurity and Biodiversity Working Party, says the plant is an issue because it's a tough, fast-growing vine that can rapidly climb and smother native and exotic trees.

"It grows equally well creeping over the ground, shading out low vegetation such as regenerating seedlings," said Craw.

"Moth plant is one of Northland's worst weeds."

It's a common pest along roadsides, forest edges and coastal sites, and also a problem in urban reserves and gardens, where it can grow up to 10 metres tall.

In January, the plant can be identified by its prolific white flowers, which are about 25mm across. The flowers turn into large hanging kapok-type pods, each of which splits open to release hundreds of seeds with silky threads that are carried by the wind to new sites.

"At this time of year, moth plant vines are often heavy with flower and immature seed pods.

"It's best to tackle the plant now, as it's easy to see, before the pods can ripen and burst over the next few months.

"If pulled or dug out before the pods mature, it's not necessary to remove the vine or pods from the tree it's climbing up," explained Craw.

If caught early enough, small moth plant seedlings can simply be pulled out.

The seeds are poisonous to humans, and the pods and stems also contain a milky sap which is a skin irritant, making gloves a recommended option when handling moth plant.

Control options include spraying or removal by hand, and collection of mature seed pods.

The roots of large plants should be cut out at least 5cm underground or controlled with herbicide.

For more information, visit www.nrc.govt.nz/pestcontrolhub