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The new interest in ornamental grasses is potentially bad news for Northland farmers.

Although most grasses propagated for the garden are harmless, one species is a real threat to farming.

Needlegrass, or Nassella tenuissima, is popular for its attractive light coloured foliage and fluffy seed heads, but it has already begun to “take over” gardens it is planted in.

The plant produces thousands of seeds each season, and the seeds float some distance on the wind. Because it grows so easily from seed, needlegrass is being propagated and sold by home gardeners and organisations raising funds.

One homeowner with a particularly well tended garden in the Whangarei Heads area picked up a plant at a market a couple of years ago, and now has a dense mat of seedlings popping up over much of his garden.

For years, he will have to spray or dig out new seedlings to get the weed under control.

Although having them in the garden is bad enough, they are even more destructive in farmland. Needlegrass is not eaten by stock, so there is nothing to stop it spreading out of control on previously productive pasture.

Needlegrass is a native of Argentina, and is close relative of nassella tussock, a highly invasive pasture weed which has almost been eradicated from Northland after a campaign spanning decades and costing hundreds of thousands of dollars.

In Australia, researchers have shown that the weeds can germinate grow to maturity and seed within four months.

Any sightings of this plant must be reported in confidence, to Ken Massey at the Northland Regional Council’s Whangarei office, or to your local Regional Council offices. Regional Council staff will inspect and remove plants with no cost to the occupier.

Information supplied by Val Monk, Northland Regional Council

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