Australian Tree Fern

I saw a story about what Hawaii is doing to eradicate this invasive plant in their area, and I wanted to share it with everyone.

LIHUE, Hawaii - Kauai conservationalists and officials plan to attack the growing numbers Australian tree ferns that have invaded the heart of the island, which is pushing out native plants and endangering the area's fragile watershed.

"We're going to hit it with everything we've got — ground crews, helicopter control, plant nurseries and help from individuals — but it's going to take everyone," said Chipper Wichman, director of the National Tropical Botanical Garden.

The garden is a member of the Kauai Watershed Alliance, a consortium of forest landowners and the Kauai Water Department, that has contracted the Nature Conservancy of Hawaii to coordinate a response to the foreign plant.

The Australian tree fern may be the worst weed in Kauai's forest environment, said Trae Menard, director of the Kauai program for the Nature Conservancy.

Menard said he realized the seriousness of the fern's infestation during the aerial mapping from 2003 to 2006 of Kauai's most pristine native forest in its deep central mountains.

"We found that Australian tree fern was distributed throughout this core of our watershed," he said. "Pilots are telling us that where 10 years ago they saw five of them, now they see 500."

Wichman said the fern is such a dangerous threat because it can produce spores that spread on the wind carrying to places other species wouldn't be able to thrive.

Several major nurseries have stopped selling the fern, which is much more aggressive, faster-growing and taller than the native hapuu tree fern. Unlike Hawaii's tree fern, the Australian species also doesn't coexist with native plants and instead quickly forms one species stands that shade out anything living on the ground below.

The plan to control the invasive fern includes sending crews on foot into the uplands of Wainiha and the Lumahai valley to take out the plants. Helicopters with herbicide will be sent into more remote and dangerous areas.

A weighted spray nozzle dangling at the end of a 100-foot-long cable from the helicopter will dispatch a brief shot of herbicide to the center of each fern. A dye confirms the plant was sprayed.

Menard said the herbicide quickly breaks down in both soil and water.

"The safety of this herbicide is the message we want to get out the most," Menard said.

Makaala Kaaumoana, executive director of the Hanalei Watershed Hui, said the public doesn't yet know whether to be concerned.

"All we have is questions and no answers," she said.

A public meeting held by members of the Kauai Watershed Alliance is scheduled for Monday in Hanalei.

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I know I shouldn't be surprised but when I was at Home Depot today they were selling this nuisance. Arrrrgh!

And it figures that a couple of sad plants I purchased at Lowe's on a road trip last February for $1 is invasive....sheesh...something else to burn and it was doing so well in the pots.

I don't know if it's invasive in CA--we have a quite different climate than Florida and Hawaii. Our lack of summer rain tends to keep a lot of things in check that would get out of control in other areas.

maybe so, though it's listed as drought tolerant. It might get just a bit too cold up here as well.

There are a number of things are drought tolerant and if you live in a climate where they don't get a lot of water, then they stay nice and in control. But the second you give them more water than they really need to survive, and they take off like crazy. Romneya coulteri is a nice well behaved native here, but you get up too far north into the Portland/Seattle areas and it becomes a rather aggressive invader because there's so much more rain. I honestly don't know one way or the other with this one because I've never researched it, but I've never heard that it's a problem here (and there are several local botanical gardens growing it--I would hope they would know better than to grow invasives!)

Ah, well if the experts do it, then I guess I can. :-)