Zoo horticulture a delicate balancing act of matching plants and animals

Frank Pizzi is used to being upstaged by elephants, lions and tigers. Let's face it, you don't go to Pittsburgh Zoo & PPG Aquarium to see plants.

But don't be fooled -- what the curator of horticulture and grounds and his staff do has a profound effect on how visitors view the zoo.

Gone are the days when the animals were stuffed behind iron bars in antiquated buildings. Now the goal is to present the animals in outdoor habitats that closely mimic where they originate, be it an African savannah, an Asian forest or an Alaskan seacoast. And plants play a prime part in that scenario.

When Pizzi landed his position 22 years ago, he had no idea what he was in for. The world of zoo horticulture was in its infancy, and he wrote the rules as he went.

"This is a place you never get bored," he says. "We are very busy."

These days, as he moves from one area of the 77-acre facility to the next, he seems to thrive on the motion. He's responsible for long-range horticultural planning, making plant choices for the collection, designing seasonal plantings, scheduling regular maintenance of the grounds and supervising the day-to-day activities of his staff, which includes an assistant, three full-time employees and 14 seasonal workers. Sometimes, you might even find him weeding beds.

Education is the byword, and Pizzi and his staff work industriously at creating illusions to further that cause.

"We try to mimic some sort of snapshot of the animal's habitat. Within that habitat we want to give (the visitor) as much information on habitat as we can ...

"It's a lot of smoke and mirrors here," he says, laughing.

For instance, they'll use plants like barberry, which will grow here, but his staff will hand-thin them to appear spindly like a plant that would grow on the African savannah.

The planning process from concept to creation can take years.

"We do it in stages," he says. "We sit down with the animal care staff, study the animal, the environment, where it comes from, the climate.

"We try to look at the overall picture, what this animal needs, what other plants or features are key to understand it."

The animals have evolved to use the habitat they survive in, including the plants, Pizzi says, so the goal is to figure out how best to represent that habitat within the constraints of the zoo, our climate and, of course, the budget.

Making a plant list isn't as easy as it might seem because he is dealing with expensive zoo animals, and plants can be poisonous.

"We have a list of plants that are toxic to horses, cows and sheep. We use that, plus we get information from other zoos about toxic plants," Pizzi says.

Something as simple as wisteria pods have made gorillas sick at another zoo. When a walrus at a zoo ingested pine cones that fell into its tank, it caused a blockage that resulted in the death of the animal.

Finding the plants on the list can be frustrating, he says.

"We have to deal with the commercial plant industry. We are looking for obscure native plants, things that aren't really used much," he says.

Sometimes the list is revised three, four or five times, depending on plant availability. Then, just when they have found the right plants and installed them, some are destroyed by the animals.

"Some plants (in any habitat) are considered sacrificial. It's just like turning small kids loose in a china shop. Something is going to break," he says.

It isn't just the animals that get to the plants; disease and insects get to them, too. Unlike other horticulture professionals who have an arsenal of chemicals at their disposal, Pizzi doesn't. No chemicals are sprayed at the zoo because it's filled with people and animals. Instead, he follows Integrated Pest Management, the use of beneficial insects to keep problems at bay.

"The goal is to have a balanced environment in which things thrive without much outside management," he says.

If things get bad, they can occasionally use something like soybean oil. But if a pest destroys something, like a stand of white pines in the Asian forest habitat, they'll have to be replaced with something more resistant.

Besides these tasks, Pizzi is also in charge of designing and maintaining the displays around the service areas and concession areas, and things as mundane as lawn care. He recently put in a pollinator habitat by the parking lot to help educate people on the importance of bats, bees and other insects in the environment, and he re-installed a butterfly garden by the children's area.

Of course, he always wants things to look good.

"The education starts at the parking lot," he says.

One of the nice things about the pollinator habitat is that it requires little maintenance, a huge issue at the zoo. Work is done as much as possible during times when visitors are not at the zoo. Pizzi and his staff are revamping and tweaking constantly as they look forward to new challenges.

"People wanted to keep the zoo the same. When we tore out the old building, people complained ...

"Now the children educate the parents, explain it to them, to look for a habitat, which sparked a new interest.

"They get it," he says simply.