Stealthy invader
Puncture vine gains ground throughout county, sparking complaints, search for answers

By Larry Meyer
Argus Observer
Wednesday, September 2, 2009 10:27 AM PDT

It starts out small, but puncture vine can grow to carpet the ground in a short time. The vine has become well-established in Malheur County and is gaining ground every year.

VALE — Much less visible than koshia weeds — puncture vine, or goathead — has evolved into one of the most prolific weeds in the county, and one rural Vale resident said people need to take action to get the plant pest under control.

Jack Marquis, Vale, said people should take the responsibility to spray or clear their own driveways of the weed and spray along the roadways in front of their own properties. “The county can’t do it all,” he said, adding it has budget problems. “We’ve got to fight it all the time.”

Malheur County Weed inspector Gary Page conceded puncture vine is spreading fast and far.

“It’s really bad this year,” Page said. “It’s really worse than I’ve ever seen. People are pretty upset.”

According to Goatheads.com, it only takes two to three weeks from the time the seed sprouts, blooms and starts more seed. The seed coat can last up to 20 years, and each burr has five segments, with two to four seeds each, the Web site said. The weed can also be transported in vehicle tires and in livestock feed.

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The weed is already established as far out as Juntura, Jordan Valley and Arock, Page said.

“It’s being spread a long way,” he said “It’s vehicles and ATVs.” Page also said much of the vine is rooted in area canal banks. However, a lot of it is along roadways, in vacant lots, in parking areas and along driveways.

Clint Shock, Malheur Experiment Station superintendent, agreed that it will take a  united effort — and not just intervention from county government — to solve the puncture vine challenge.

He said it is an issue of “good neighborliness” to keep certain weeds, such as puncture vine, from spreading off one’s property to next door.

“It needs to be controlled earlier,” he said. “It’s all over the place.”

He and Page attributed the growth of the weed this year to rains in May and June.

Puncture vine is relatively easy to kill with herbicides, Shock said. Another way is to dig it out with shovel or hoe it out. Shock said it is important to cut tap root and get as many burrs as possible. Another way to control the weed is with a burner. The heat opens the seed pod up to expose the seeds, which will rot or be eaten by insects, Page said.

In some southern states, a biological control is proving successful — weevils that feed on puncture vine and puncture vine only.

“We have released weevils since 1988,” Page said.

The problem is that in the colder climates they die out during the winter. Researchers have been trying to acclimate the weevils to the colder region and it remains to be seen if they will be successful, Page said.