California is being overrun by non-native plant life
By John Loesing
Acorn Staff Writer

LISA ADAMS/The Acorn WEEDS BE GONE--Jo Kitz, vice-president of the Los Angeles/Santa Monica Mountain chapter of the California native plant society, pulls up a "Yellow Star Thistle" weed at Malibu Creek State Park.

Spring is back, and so is Arundo Donax, the fast-growing, bamboo-like weed that badly chokes the area’s rivers and streams and often leads whole communities to fight against it.

Agricultural experts estimate more than 90 percent of Southern California’s riparian habitat has been lost to Arundo Donax, a reed that can grow several inches a day during the warm weather and up to 25 feet tall.

Weed abatement efforts by the Los Angeles County Department of Agriculture and private groups have significantly reduced the amount of Arundo growing on the banks of Cold Creek in rural Calabasas, but other patches thriving along Malibu Creek and Topanga Creek still have authorities worried.

The plant also grows along Arroyo Conejo Creek between Thousand Oaks Boulevard and Hillcrest Road, and in the North Fork Conejo Creek as it enters Wildwood Park.

Other invasive plants are popping out this spring, too. Medea Creek has a problem with perennial pepper weed, castorbean and tree of heaven, but Arundo remains public enemy No. 1.

"It just crawls into everything. It’s the kudzu of California," said Nancy Helsley, director of the Santa Monica Mountains Resource Conservation District and a resident of Cold Creek.

Why does a tall green plant once popular for building homes and making musical instruments draw such ire today? Because it spreads unchecked and now threatens the health of streams and waterways practically statewide, according to biologists and land management professionals.

The plant comes from India and has been cultivated in Europe, Asia and Africa for centuries. Spanish settlers brought Arundo from the warm, Old World climates to be harvested as fodder and roofing material in California. Locally, the plant spread from the Los Angeles River to other wetland areas, growing with impunity and knocking out existing vegetation such as willow, cottonwood and mulefat.

"It has absolutely no enemies, and this is why non-native plants can do so well," said Jo Kitz, a member of the local chapter of the California Native Plant Society.

"They evolve in climates similar to ours, but here they are brought in without their control factors so they have no insects, no pathogens, nothing to check them." Kitz said. "They can just breed with contempt."

Arundo played an important role in the development of music as the cane became part of the original Panpipe. The plant is still used today to make the reeds for woodwind instruments, but opponents are no longer singing its praises.

From California’s South Coast into the deserts and up to the Sierra Nevada Mountains, war is being waged on the weed. "Team Arundo Conejo" and "Team Arundo del Norte" are examples of regional groups on a self-appointed mission to seek and destroy Arundo.

Among other things, Arundo is said to consume three times more water than native plants. It supplies no food or nesting habitats for native animals, and once it gets tall and dries out, it becomes an extreme fire hazard.

The California Department of Food and Agriculture (CDFA) has placed Arundo on its list most invasive, even noxious pest plants requiring "eradication, containment, rejection,or other holding action at the state and county level."

Although nursery organizations are opposed to what they see as an indirect assault on the retail plant business, the CDFA remains dedicated to the creation of "weed management areas" throughout the state, including one soon to be established in Los Angeles County.

"We’re excited about it. We think this is really a good resource to start dealing with some of these problems," said Susan Nissman, a spokeswoman for Supervisor Zev Yaroslavsky and a weed management advocate.

Arundo is eradicated by spraying it with herbicide or by cutting it down and immediately applying chemicals to the cane stump. Rodeo and Roundup, two herbicides from the Monsanto Corporation approved by the Environmental Protection Agency for fighting Arundo, are said to be safe, non-cancer causing agents.

Not all to blame

According to figures from the Nature Conservancy and the University of California Davis, Arundo is one of 1,023 non-native plants species established in California over the past two centuries.

Another one with a sticky reputation is the yellow starthistle, a bushy, two- to three-foot tall weed said to poisonous to livestock.

Accidentally introduced from Europe, the starthistle now grows on more than 20 million acres, but Craig Dremann, a Northern California environmental consultant and re-vegetation expert, said the plant covers the land "by default rather than by aggressiveness."

"Starthistle is growing where the natural ecosystem has completely collapsed, in areas so poor in species and nutrients that even exotic weed grasses have difficulty surviving," Dremann said.

The yellow starthistle for many years had only a minor presence along Kanan Road, but nourished by El Nino, it spread greedily into Malibu and Topanga. It also can be found in copious quantities along the Cold Creek equestrian trails and along most any roadside shoulder where grading has produced exposed dirt.

Dremann advocates that Caltrans use alternative vegetation practices along the highways, not only to bring native plants back into existence, but to reduce the use of herbicides.

"You substitute the grasses that dry out in the summer, plus the starthistle, and you put back in the California perennial vegetation, which stays in place year round and doesn’t open the doors for other weeds to get established," Dremann said.

Basically, any vegetation that turns brown in the summer isn’t from California, Dremann said, and when these European-based plants and grasses shrivel and die, they allow the invasive weeds to take over.

He suggests reintroducing the native purple needle grass, for example, to help restore nature’s balance.

"You want to put some plants out there that are going to do the job for you 24 hours a day, seven days a week rather than you having to be the gardener or the vegetation manager," Dremann said. "You establish plants that will keep the weeds out permanently. You don’t think about eradicating the weed, you think more about what you want in its place.

"For the past 50 years, as long as we’ve had herbicides, we’ve always had this focus of eliminating the plants we don’t want. Instead we should be thinking, if we could wave magic wand tomorrow, what kind of vegetation do we want actually growing there?"

Anything but Arundo, whose opponents have become as fast-growing as the weed itself.