Tough Little Plants Don’t Survive Term in Nursery

It’s a tough little plant--hardy enough to grow without much water or soil in the cracks of boulders in the rugged foothills northwest of the San Fernando Valley.

But the rare Santa Susana tar plant apparently isn’t tough enough to survive a $16,000 experiment to transplant the plants from a construction site above Chatsworth.

Only nine of 55 tar plants harvested from a rocky hilltop last summer to make way for a 95-foot-wide water tank have survived at a specialized nursery in San Juan Capistrano, officials said.

The ill-fated harvest has angered plant experts, who contend that the Santa Susana tar plant could soon be wiped out of its original habitat by developers.

The tar plant is known as Hemizonia minthornii to botanists, who have placed it on the state’s list of rare plants. It grows in bowl-like clumps on rocks and has narrow, sticky leaves. It blooms with nickel-size yellow flowers in late summer.

Other than on the rocky outcroppings above Chatsworth, the Santa Susana tar plant has been found only on two isolated ridges in the Santa Monica Mountains north of Malibu.

Construction of housing in the Santa Susana Pass area destroyed hundreds of tar plants last year, however, naturalists have complained.

So when the Las Virgenes Municipal Water District decided to build a $1-million water tank to serve the new homes, water officials quickly realized that the 1 1/2-million-gallon tank would be in the middle of prime tar plant territory.

A survey of the proposed half-acre tank site, adjacent to an existing smaller tank, showed 125 tar plants. But because the hilltop elevation was needed for proper water flow, water officials decided to proceed with the tank project after undertaking a first-of-its-kind tar plant transplanting.

Taken to Nursery

Fifty-five plants were collected at the site in August, according to officials of a Ventura engineering consulting firm that organized the harvest. The plants were placed in pots containing soil from the Chatsworth area and taken to the Tree of Life Nursery in San Juan Capistrano.

Duane Vander Pluym, an engineer who helped oversee the harvest, said there was optimism that the uprooting would be a success--even though no one had tried to transplant a tar plant before.

“It grows practically in bedrock. That gives you an idea of the relative hardiness of the plant,” he said.

But the tar plant takes to cracks in sandstone boulders more than to careful cultivation in plastic pots.

“Only nine survived,” said Jeff Bohn, co-owner of the nursery, which specializes in native California plants. “It was the shock of transplanting. It was probably the wrong time of the year to transplant them. But we think that all that mortality is over with. Those that are alive should do well.”

Germinating Seeds

Bohn said about 2 ounces of tar plant seeds also have been salvaged. An attempt is being made to germinate them so that the seedlings can be replanted around the tank, which is being built north of the Simi Valley Freeway and west of Topanga Canyon Boulevard.

The high loss rate does not surprise some plant experts.

“What did they expect?” asked Steve Hartman of Sherman Oaks, former president of the Santa Monica Mountains chapter of the California Native Plant Society.

“This concept that developers can pull rare and endangered plants out of the ground with the idea of keeping them in suspended animation until they can replant them runs against the concept of native flora,” Hartman said.

“It’s as bad as taking rare and endangered animals out of the wild and putting them in a zoo.”

Tim Thomas, a Santa Monica Mountains park ranger and professional plant geographer, said he fears that the transplanting will set a precedent.

Instead of cutting back on grading, builders will simply dig up endangered plants and announce plans to replant them after construction is finished, said Thomas, a volunteer rare-plant specialist for the California Native Plant Society.

Relocating the ‘Problem’

“The whole concept of transplanting rare species is a convenient way of saying you can relocate the ‘problem,’ ” he said.