A Brush With Nature : Santa Monica Mountains: Young offenders attack the Spanish broom, a weed choking the native flora. As a result, grasses are returning.

A broom from Spain is sweeping through the Santa Monica Mountains, and it’s leaving an environmental mess.

But the National Park Service is striking back, literally attacking the Spanish broom--an exotic plant that is killing off native flora--at the roots. On Thursday, a crew of seven inmates from a juvenile probation camp took up hatchets and “weed wrenches” to chop, hack and yank the plants from a rugged hillside a few miles south of Agoura Hills.

It was the first government-sponsored campaign against the Spanish broom, so named because it resembles a dried broom shoved handle-first into the earth.

“It’s displacing the natives,” said Rose Rumball-Petre, a resource-management specialist with the Park Service. As tall as it is resilient, Spanish broom crowds out some plants, like the yucca, and also blocks the sun, killing off surrounding--and shorter--natives. “In other words, it’s smothering the other plants,” she said.

Many California native grasslands in the region, said Rumball-Petre, are slowly disappearing in the 150,000-square-acre Santa Monica Mountains National Recreation Area, which extends from Point Mugu in the north to Griffith Park in the south.

“We’re here to preserve and protect the plants by removing the Spanish broom,” Rumball-Petre told a crew from Camp Miller, a county probation camp for juveniles in Malibu, that gathered on a cold, sunlit morning. “I think it’s important to know why you are here,” she added, concluding her pep talk.

The teen-agers, who had been assigned to the work detail, didn’t respond and set to work.

For three days this week, about 200 square feet of parkland shrouded by the invasive Spanish broom have been cleared with the help of work crews from Camp Miller. “For the trained eye, to see native grasses poking out again, I can’t tell you how wonderful that is,” Rumball-Petre said.

She then showed the young men wearing yellow hard hats, sweat shirts and jeans how to use the weed wrench, a long pole with a clamp on its curved end that relies on leverage to pull the plant from the ground, often with the roots intact.

“Why can’t we just chop them down?” asked 17-year-old Raul. She explained that chopping would take too long and was too tiring. Besides, the roots have to be removed to prevent the plant from growing back.

The day before the inmates arrived for work, probation officer Frank Robinson explained what their task would be. “Some of them complained, asking, ‘Why do we have to do this?’ ” he said. “They think it’s some sort of punishment.”

But once they get outside, work a little and maybe see an alligator lizard or a rat, Robinson said, the city kids begin to understand why they are digging up these weeds. Most of Thursday’s crew did not show such enthusiasm, but one said he’d like to come back as a volunteer when he completes his sentence at Camp Miller.

The Spanish broom was introduced to the region’s mountain ranges by the Spanish settlers in the 18th Century to control erosion.

Rumball-Petre conceded that although the work crew removed mounds of the plant, new ones will sprout as seeds are scattered by animals or the wind.

Some non-native plants can be burned or poisoned, but those options were rejected for the Spanish broom, said David Gackenbach, superintendent of the Santa Monica Mountains National Recreation Area. It was feared that herbicide would harm plants nearby, and fire was ruled out because the location, near Kanan Road and Mulholland Highway, is not far from some houses.

Carlos, 17, like some other workers Thursday, had never been to the Santa Monica Mountains before his stint with the work crew. “I like working out here, cleaning up,” he said. On his second day pulling up Spanish broom, he said he had mastered the technique.

“You gotta look for the right way to do it. If you do it any old way, you could be here all day long.”

Spanish Broom Facts

Spanish broom, Spartium junceum , is an aggressive spreading plant that is displacing native flora in the Santa Monica Mountains. An almost leafless shrub member of the pea family, it has bright yellow flowers.

* Origin: Spain. Flourishes in Mediterranean climates.

* Height: Up to 12 feet.

* Reproduction: Seeds scattered by winds and animals.

* Range: Prevalent on dry slopes in the eastern half of the Santa Monicas but also found as far west as Ventura County.