PLANTS: Another Dimension at Zoo : Rare Plants Add a Dimension to Zoo’s Attraction

To the casual, fleeting zoo visitor, they may pass quickly in front of the eyes, never to be noticed, never to be treasured. Obliviousness is their albatross, being taken for granted their fate.

They are plants. They are, at best, supporting actors in the howling milieu of the San Diego Zoo. Although they stand out prominently at times, they can hardly compete with the growl of the gorilla, the prance of the panther or the graceful elegance of a giraffe.

They are, however, worth more than any such species. Zoo officials note that the more than 5,000 kinds of plants are worth millions of dollars. (Exactly how many millions isn’t said.) An indication may be found, however, in the annual budget for the zoo’s horticulture department--a tidy $800,000.

About 1,000 species are “threatened,” as endangered as the animals whose homelands they share. They include staghorn ferns, cycads, palms, orchids, almost all cactus, and dozens of others.

“If you destroy habitat--and that’s the main reason animals are endangered--then what else do you also destroy?” asked zoo tour guide Susan Smith. “Plants--that’s the one thing most people don’t think about.”

Smith said the age and rarity of the plants, not only at the zoo but also at the Wild Animal Park, make them more valuable than the animals. Of the endangered, cycads are the oldest and rarest.

Palms and bamboo are among the more plentiful, which should be good news for the panda if any ever arrive from China. (Bamboo, disappearing from the face of the earth, is the panda’s main food. The San Diego Zoo is, however, full of bamboo--an attractive tool, Smith said, for one day wooing the panda.)

Dale Ward is the owner of Offshoot Botanical Tours, an independent group showing plant lovers the virtues of the zoo’s vast collection. He worries that too many people take the plants in the zoo for granted.

“I deal with that all the time,” he said. “Even the people who manage the zoo look at horticulture largely as maintenance--sweeping the sidewalk, sweeping (up after) the elephants. They don’t appreciate the aesthetic or artistic value of plants and aren’t really marketing the zoo’s botanical side. To them the idea is to push as many people as possible through the turnstiles.”

Ward thinks that a good way to “hype attendance” would be to push the botanical side, a beautiful garden--one containing a few thousand furry distractions. He said the zoo once held a “botanical breakfast tour,” complete with coffee and Danish with an expert’s tour of plants. It was, he said, a smash hit--one that was soon excised.

“Not ‘cost-effective,’ ” he added. “So, it was cut. If the zoo would advertise a botanical tour, I know they’d get a huge response.”

(Zoo spokesman Jeff Jouett noted, however, that tours of the plants are conducted by the zoo, either monthly or on request. Any group of 15 or more can make a request and receive a 3 1/2-hour or two-hour tour of the zoo’s plants. But that includes the primates as well.)

Ward is convinced that even those who feel blase about plants would marvel at the wonders of cycads, the leafy, palm-like trees sprouting from a pineapple-shaped cone. Apparently, they’re as difficult to grow as it is to find a cure for old age. Cycads have, however, done well in defying old age. They may be the ablest survivors on the planet.

“The oldest living genus of plants in the world,” Ward called them. “They were thriving over 150 million years ago in the age of dinosaurs. Now, however, they’re on the way out. Their habitats are being destroyed. Tropical places, mostly--Java, places like that. Man is killing them--man and his big, bad development.”

Under the direction of Bill Knerr, the propagator of plants at the zoo, cycads are being grown as the product of a far-sighted, bizarre experiment. When male cycads come into bloom, Knerr and co-workers collect the pollen and freeze it in botanical freezers (containing liquid nitrogen). When the females mature, they’re pollinated by hand. A nifty process, but Knerr notes that 150 years are needed to get cycads even a few feet high. And 15 males are needed for every one female pollinated. Another reason cycads are disappearing is that they are scavenged by collectors wherever they grow.

Knerr--a lean man with sandy hair, tinted glasses and a safari look, in his khaki pants and shirt--has worked at the zoo 10 years. He grows plants not only to preserve embattled species but also for ornamentation of the park--and to feed the second-most-valuable holding, the animals.

“The gorilla,” he said, citing one example, “eats xrag

a ginger plant from Africa. He eats the whole stem, then pulls it through his teeth like a corncob. We get the seeds from Africa, then grow it here.” At first they were having no luck growing it, “then we found out by accident that it grows well in the ruts of roads. Haven’t had a bit of trouble since.”

Knerr has flown to Central America and come back through U.S. Customs bearing armloads of plants and seeds from the loamy soil of Panama and Guatemala. He has had plants and seeds stored in refrigerators in Paris and has grown thousands of plants in greenhouses all over the zoo.

Orchids, another endangered species, are among his latest projects. He’s growing those with the help of a $22,000 grant from the San Diego Orchid Society. Thirty years from now the zoo hopes to have all plants and animals arranged “bioclimatically,” that is, by region and temperature. Cats, for instance, will not necessarily remain among all other cats, or primates with all other primates.

“All areas of the world are diverse in variety,” said tour guide Susan Smith. “It’s the same way with plants and animals. You don’t have an area of nothing but hemlock, nothing but gorillas.”

In such areas Knerr will still be growing eucalyptus for koalas, eugenia for golden monkeys, acacia for giraffes. He’ll still fit in the macadamia nut trees, the agave plants (from which tequila and mescal come), aloe plants (from which aloe vera comes), as well as the occasional bird of paradise plant. And he’ll still be touting a need to save plants, wondering how anyone could possibly overlook them.

“In my mind, they’re irreplaceable,” he said. “They’re so rare, so precious. It’s hard to put a value on a 50-, 60-year-old tree. It’s like asking what kind of value you put . . . on a human being.”