Print Town of Camp Verde escalates war on weeds
Written by Mark Lineberger   
Saturday, 03 March 2012 00:00

They might just have to nuke it from orbit.

Actually, that might be a little beyond the Town of Camp Verde’s technical resources, but the Town Council last week stepped up its battle against noxious, invasive weeds, particularly one that can be toxic to horses.

At issue is the yellow starthistle, a thorny weed that’s shown up in Camp Verde over the past 12 years, said Jeff Schalau with the University of Arizona Cooperative Extension Office in Yavapai County.

Yellow starthistle (Centaurea solstitialis) is an invasive weed that occupies grasslands, open woodlands, fields, pastures, roadsides and disturbed areas. It has become established on the south end of Camp Verde.The plant, native to Eurasia, first showed up in California in the mid-19th century, thought to have been brought up on a shipment of alfalfa or something similar from South America, where it was possibly introduced by the Spanish.

Today, the plant is rampant in parts of California. So far, Camp Verde and Peeples Valley are the only two spots in Yavapai County where a major spread of the plant has been noted, Schalau said.

In Camp Verde, the plant has taken particular root in the area between Clear Creek and Quarterhorse Lane.

“It seems like it should be an easy weed to manage,” Schalau said, “but the problem is it produces so many seeds.”

That’s a bit of an understatement. Schalau said a single plant can produce as many as 150,000 seeds.

The seeds also lie dormant for various periods of time, Schalau said, meaning that even if you think you’ve gotten rid of them, more plants could start to grow the next year.

That’s something Town Councilman Alan Buchanan knows firsthand. At the Feb. 22 council meeting, he said he’s been fighting the plant on his property for the past few years.

“Every year I keep on thinking I’m done with it,” Buchanan said, estimating he’s pulled thousands of the weeds only to have them keep popping back up.

“Watch for seedlings coming up 10 years from now even if we decide to throw everything we have at it,” Schalau said.

While the plant is poisonous to horses, Schalau said a horse would have to eat about 1 percent of its body weight of the dry weeds before the effects could become harmful.

It causes a form of brain damage that prevents a horse from chewing food, Schalau said.

Younger horses may be more at risk, Schalau said.

The seeds can hitch a ride on vehicles, animal fur or even a pant leg.

“It reduces plant diversity and reduces soil moisture,” Schalau said. “They’re not particularly a pleasant plant, particularly if you have to walk through a field of them.”

There are ways to fight the invasion, Schalau said. Cows are poisoned by the plant but can eat it. There are also a few types of insects that can be introduced to feed on the weed’s larval seeds, Schalau said. Other forms of combating the weed, through chemicals or fire, might not be as effective if they also harm the plants that compete with the yellow starthistle for resources.

It can be difficult to fight the plant, particularly since seeds have no regard for whether they are on private or public lands.

Enforcement of nuisance laws can only go so far, and by the time they are triggered, Schalau said it may already be too late to stop the spread.

That’s why the real key to the problem is educating landowners about how to fight the weed, Schalau said.

To that end, the Town Council, on a motion by Councilwoman Jackie Baker, voted to work closely with the extension office and groups like the Verde Natural Resource Conservation District to use all available measures to control the weed along with developing an effective education program for residents.

While the town’s staff gets to work on this directive, there’s one thing that’s certain.

It’s going to be a tough fight.


Mark Lineberger can be reached at 567-3341 or email This e-mail address is being protected from spambots. You need JavaScript enabled to view it