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Goathead Avengers on the Roads

Local bikers stick it to puncturevine


It's an all too familiar scenario if you've ever ridden a bike in Boise. One moment you are cruising carefree down the Greenbelt, then suddenly one of your tires starts to thump and your bicycle begins to swerve. Cursing, you come to a halt and, behold, a diabolic spike is imbedded in the tire rubber.

The goathead is the arch nemesis of all bike tires and an unfortunate reality of being a bicyclist in Boise. But one group of bikers isn't taking it lying down. The Goathead Avengers have had enough and are taking the fight to the streets.

"If there was a weed that posed as much of a threat to automobile tires as goatheads do to bike tires, you can bet the city would be on a four-alarm abatement program on the double," said Casey O'Leary, founder of the avengers. O'Leary runs Earthly Delights, an urban farm, and is well acquainted with digging weeds.

The idea behind the Goathead Avengers is simple: enjoy a few beers with friends, then lay waste to goatheads. Still in its fledgling stage, the group has been meeting since May to make biking a more puncture-free venture in Boise. Basing their beer-fueled forays on a league of superheroes, some early rides involved avengers clad in costumes. This was pragmatically dropped because of the difficulties posed wearing a cape while riding a bike. Nowadays, the avengers just use their powers to destroy goatheads and aren't concerned with looking the part.

The stalwart group of six, including an herbalist, a technical writer and a Boise State philosophy professor, started a recent outing with beers at Table Rock Brewpub. They didn't have far to ride to find their objective--not a block away, a slew of goatheads grew alongside Capitol Boulevard. Leaping off their bikes, gardening tools and trash bags in hand, the avengers laid waste to the enemy.

Fighting goatheads is a Herculean task. Casey Robinson, a bike technician at Capitol Schwinn Sports, has seen more than his share of tires ravaged by the weed.

"I don't think there's much that can be done. It's like trying to get rid of rabbits. They're always making babies," Robinson said.

Robinson believes the best line of defense is puncture-resistant bike tubes, which boast about six times the thickness of a standard tube. Filling those tubes with self-sealing slime creates a bike tire that is nearly goathead-proof--a necessity in an area notorious for goatheads, Robinson said, adding he sees at least five goathead victims each day at his shop.

Goathead, also known as puncturevine, or Tribulus terrestris as binomial nomenclature would have it, is indigenous to the warmer areas of Eurasia, Africa and Australia, but grows extensively across the western United States as an invasive species. Boise's cold winters keep it as an annual here, whereas in its warmer native lands, it grows as a perennial.

The seeds can lay dormant for half a decade, making it exceptionally difficult to get rid of. Despite being a nuisance, goathead has medicinal qualities and has also found some popularity as an aphrodisiac. The avengers even brew a surprisingly tasty tea from dried goathead plants.

The true origin of goatheads in Boise has passed into myth along with the culprits responsible. One legend holds that the wardens of the Old Idaho Penitentiary planted goatheads around the prison grounds to deter inmates from escaping. Another rumor boasts that goatheads were brought in by the railroad to prevent erosion around the tracks. Still another claims that goathead seeds were shipped in with feed for a field of polo ponies.

While the avengers focus on city-dwelling weeds, another group is taking the battle to the Foothills. Rich Gardunia, head trail ranger for the City of Boise's Parks and Recreation Department, also leads a platoon of garden tool-wielding vigilantes.

"The goatheads are worse than ever this year," Gardunia said. "We got just the right combination of temperature and rain. This is the first year they've ever been this high in the Foothills."

Once a week for the last month, Gardunia and a dozen volunteers patrol the Ridge to Rivers trail system to pull the weeds. Goatheads, along with some 50 other invasive species, are on Idaho's noxious weed list, and for now Gardunia said the best option for getting rid of them is just to pull them.

For aspiring avengers, the first lesson in fighting goatheads is learning to recognize them.

"You'll feel it before you see it," warned O'Leary. Goatheads easily poke through bike tires, flip flops or even dog paws, so gloves and a healthy dose of caution are crucial when dealing with this floral foe. Goatheads thrive in abandoned parking lots and untended yards.

"The crappier area, the better," said O'Leary.

Despite its prominence, the plant blends in well, especially among similar vegetation. A plant called spurge is often mistaken for goathead. Spurge has a comparable leaf structure and grows low to the ground, but spurge has a purple flower whereas goatheads have a yellow flower. Moreover, some well-intending people manage to spread goatheads while trying to remove them. The trick is to get the plant before it goes to seed.

"If it hasn't seeded, just dig it up. If it has seeded, throw it in the trash," said O'Leary.

Like a league of superheroes, the avengers are earning the gratitude of the populace they fight to protect, one plant at a time. While the avengers dug up the weed last week, more than one eye turned from passing traffic. "Thanks, you guys. I'm a road bike rider. I love you," said one man after hearing about the mission.

An hour later, the avengers were at the abandoned house on Myrtle Street owned by Sen. Jim Risch, where the lawn is overrun by goatheads, not a quarter of a mile from where the group started.

"There are so many people avenging goatheads on their own," O'Leary said. "In order for Goathead Avengers to work, there's got to be hundreds doing this. And the thing is, it's totally possible."

But regardless of the cause and enthusiasm of the participants, the turnout to Goathead Avengers meetings has been low, and the movement slow to catch on. Despite recruiting at local bike clubs, Boise's prominent biking community has given the avengers little notice.

Some avengers have raised the idea that, since they are doing a community service, perhaps pay incentive from the city or involvement from neighborhood associations would help turn the tide of war. Until then, the avengers will ride on and fight the odds, but watch your bike tires. The goatheads still have the upper hand in this battle.

To become a Goathead Avenger, visit, or to take the battle to the Foothills and check out