SANTA CLARITA -- Popular in landscaping for more than a century, an imported bamboo-like plant that has invaded the Santa Clara River is blamed today for all sorts of disasters -- from water shortages to flooding, wildfire and loss of wildlife habitat.

[Arundo donax], a nonnative species that grows to 25 feet high, is the target of a multipronged eradication effort on waterways from Acton to Oxnard. The plant is thick in sections of the Santa Clara River in Valencia and officials downstream in Ventura County want it out before it spreads their way.

"It is flourishing," said Megan Wong, a biologist with the U.S. Fish and Wildlife Service. "It's drying up our river systems. It spreads pretty fast and if we don't watch it, our rivers are going to run dry."

[Arundo donax] sucks up water, and because it is nonnative, it damages the delicate balance of the river's native plant life. It spreads quickly and can block runoff in a storm, resulting in flooding. In the summer months its enormous stalks dry out and create a fire hazard, said Peggy Rose, grant writer for the Ventura County Resource Conservation District. In fact, Los Angeles County firefighters blamed the hardy plant in part for the rapid spread of a fire last year that started in Val Verde and raged to Simi Valley and Moorpark before returning to Stevenson Ranch, where it threatened homes for two days.

Fish and Wildlife officials are in the midst of a plan to eradicate [Arundo donax] and another nonnative, a flowering plant called tamarisk, from the Santa Clara and its tributaries. The preliminary plan is due to be complete this summer, but it could be two years before it is implemented as participating agencies review it and river restoration plans are drafted, Wong said. The goal is to draw up environmental restrictions for removing the plant to ensure the river habitat is protected.

"You can't just go in there with a bulldozer," Wong said.

Ventura County's Resource Conservation District is funding the study with part of a $1.5 million federal grant, and the city of Santa Clarita is providing technical assistance. Much of the problem is in the city, but Ventura County, which relies on the groundwater that flows beneath the river, is concerned that the water-sucking [Arundo donax] will spread downstream. The removal plan focuses on clearing the plant to the east end of the river first to limit the spread.

"You're spinning your wheels if you start in downstream and move up," said Heather Merenda, a planner for Santa Clarita.

The U.S. Forest Service has claimed success in battling [Arundo donax] in San Francisquito Creek, a branch of the Santa Clara. In 1995, the growth was thick when biologists began their attack. Now, as quickly as sections of the river are cleared, water puddles quickly become visible, said Nancy Hanson, a wildlife biologist for the Angeles National Forest stationed in Saugus. The forest services pay Los Angeles County crews to cuts the stalks, then use a chemical called glyphostate to kill the stubborn root system. A small amount of the herbicide is dabbed on the roots to guard against harming other vegetation, Hanson said.

Roots can dig as much as three feet below the surface and regenerate under the toughest conditions. Experts tell of an experiment in the San Fernando Valley where an [Arundo donax] root ball was chopped up and tossed atop a tin-roofed building in the summer heat for several days, only to sprout after being watered.

Because it's so hardy, removal efforts involve years of returning to treat the roots with the herbicide.

"I set it up for seven years of monitoring [Arundo donax] removals," Hanson said.

The forest service moved quickly on the [Arundo donax] before it destroyed habitats for endangered species found in the creek bed. It's taken longer to treat the waterways of Santa Clarita and Ventura County, though plans are moving forward. Last week, the city hosted a conference for contractors interested in bidding on the project. The first target will cover about 296 acres of the Santa Clara, from its south fork near Valencia Auto Row to San Francisquito Creek, which runs along McBean Parkway, Merenda said.