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Zoo horticulturists lovingly tend each acre of the park, feeding animals' appetites and visitors' souls.
By Valerie May
A butterfly garden, an eagle’s perch, and wolf dens. Climbing structures for bears and a jungle gym for apes. The elegant curves of Olmsted Walk and the whimsy of a triceratops statue named Uncle Beazley. What do they all have in common?
In a word, horticulture. Each of these features, like many others, benefits from the dedicated care of the Zoo’s 14-member horticulture team, headed by park manager Frank Clements. The team passionately and skillfully maintains the 163 acres of urban parkland that make up the Smithsonian’s National Zoo. “And I’ve been on every acre,” says Clements, who’s been with the Zoo for 23 years.
Carefully tended plants create a lush habitat for a giant panda. (Jessie Cohen/NZP)
Those 163 acres divide into two parts. Seventy-eight acres envelop the Zoo’s popular attractions, home to 400 species of animals from ants to zebras. The remaining 85 acres sustain a mature forest ecosystem that surrounds the Zoo and extends into Rock Creek Park. Those woods are home to hundreds of wild animals, including whitetailed deer, Virginia opossums, raccoons, pileated woodpeckers, and black rat snakes.
In maintaining the forest, Clements says, “we try very hard to stick to native species and remove the invasive nonnatives.” The team uses GPS technology to monitor the thousands of trees that are part of the forest.
Tulips adorn the Zoo's Connecticut Avenue entrance. (Mehgan Murphy/NZP)
The Zoo’s stewardship of the land is rooted in a strong philosophical stance. “I consider the Zoo an urban forest, and our message is about conservation and preservation of species and habitat,” says Chuck Fillah, whose portfolio as associate director for exhibits and park management includes the horticulture team. “We try to walk the walk, not just tell the story in the Zoo but demonstrate the experience.”
Habitat, Sweet Habitat
The horticulture team plays a key role in one of the Zoo’s most important challenges—creating habitats for our 2,000 animals. The team’s work forms the vital backdrop for the exhibits that amaze and educate two million visitors each year.
Renovating exhibits tops the list of the department’s most favored duties. It’s a task that often requires planning a year in advance and that makes use of the individual talents of all of the staff one way or another. “Everybody gets excited about a renovation,” says supervisory horticulturist Teresa Vetick.
“Renovation starts with a request from the curator,” says exhibit designer Brian McLaren. A few years ago, the Zoo recognized the need to upgrade the maned wolves’ habitat. The long-legged, 50-pound animals had gotten a bit too good at camouflaging themselves. “You could never find them,” McLaren explains. “And their shelters, sort of A-frame wooden structures, weren’t insulated.”
Once the renovation request had been approved, McLaren began researching native habitats, with an eye toward recreating, or at least simulating, a natural environment. “We want the animals to feel secure and at home, and we want to educate the visitors,” he says, explaining that the ultimate aim is to enable the animals to display their natural behavior.
McLaren’s research included identifying plants similar to those in the wolves’ native habitat: open forest, savanna, and marshland in South America. He also studied the animals’ dens. From there, he created concept boards illustrating various options. The relevant curator, biologist, pathologist, nutritionist, veterinarian, and keepers all weighed in on the final design.
Once approved, the “board” became a blueprint for the exhibit, and Zoo staff laid out an action plan. First the maned wolves had to be temporarily relocated to the Zoo’s Front Royal campus. Then began a series of steps so highly choreographed they were reminiscent of a ballet.
Moving heavy equipment and material into the wolf yard meant going through the adjacent enclosure of the scimitar-horned oryx, a desert antelope now extinct in the wild. To minimize the disturbance to the oryx, traffic could only pass through the enclosure at set and limited times.
Under those constraints, a seven-person team led by gardener Scott Boyd spent two and a half weeks clearing the wolf yard of unwanted plants, raking out the yard, tilling the yard, raking it again, removing several dying trees, adding about 20 tons of soil, placing some 50 boulders strategically throughout the exhibit, and creating three new dens.
The dens posed something of a challenge. They had to be cave-like enough to appeal to the wolves. They also needed to be partially buried to create a warm and secure resting place for the animals. Yet keepers needed access if required. The solution: 40-inch-wide drainage tubes, five, seven, and eight feet long. Each tube had an entry point for keepers. The tubes were dug into ground and camouflaged with logs and boulders.
A maned wolf explores its habitat. (Mehgan Murphy/NZP)
Grasses—rye and prairie dropseed— have now grown throughout the yard, and Erianthus grasses will ultimately screen the holding pens in the rear. They contribute to the natural feel of the exhibit’s environment. Visitors can now easily see the wolves, sometimes described as foxes on stilts with their reddish-brown coats and luxuriant manes.
“It’s very cool seeing them standing on the highest point of their den or prancing through the tall grasses,” says Boyd. “They obviously feel secure about their habitat.” So secure, in fact, that they stayed outdoors all through last winter’s blizzards—eschewing their interior enclosures to shelter in their outdoor dens.
Reuse Your Imagination
Sometimes even a small change in an exhibit can have a major effect on animals’ well-being. Take the collared peccaries’ yard for example. Poor drainage was making their enclosure muddy and unhealthy for the pig-like mammals, recounts exhibit designer McLaren.
“We went in and removed the top onefoot layer of compacted stone and soil, and replaced it with a sandy gravel mix. It provides better drainage, and it’s much more like the southwestern [United States] habitat they are used to. Now they go out in their area, dig holes in it, and lie around. It’s a real pleasure to see them enjoying their yard.”
Billie Jean, an Andean bear, is a keen climber. (Mehgan Murphy/NZP)
And then there was the time when keepers noticed that the Andean bears weren’t getting enough exercise. The keepers sought assistance from the horticulture department to help stimulate these elusive creatures, the only bears native to South America. In their natural cloud-forest environments, Andean bears build platforms in trees and scar trunks to mark their territories. “There was nothing in the yard that really got them moving,” says McLaren. “We designed and built them a climbing structure using materials from the park. They use it a lot—especially the female and her new cubs.”
Using materials from the park is a common theme for the horticulture staff. Flexing their muscle as the ultimate recycling pros, the department converts tree limbs into gorilla enrichment toys and hollow logs into garden fountains. They provide beavers with felled tree limbs for their dam building and anteaters with rotten logs for shredding. Fillah even recalls closing Rock Creek Parkway to traffic so the team could haul several huge trees to the panda enclosure for reuse as climbing structures.
Working with the nutrition team, the horticulture team recycles many of its leftovers as browse, or food, for animals. Throughout their day, gardeners watch for materials they can harvest. Elephants and apes enjoy leafy browse from hardwood trees; giant and red pandas love chomping bamboo; and beavers, gazelles, oryx, and donkeys all benefit from munching homegrown vegetation. Much of the browse for Zoo animals comes from the park. Seeing the fruits of their hard labor and active imagination put to good use by the Zoo’s animals is one of the most rewarding aspects of the job, say horticulturists.
Of course, not every plant is suitable for Zoo animals. Any vegetation, from plantings to browse to enrichment structures (zoo-speak for logs, perches, and other materials the animals interact with) first gets approved by nutritionists, pathologists, veterinarians, and animal curators for toxicity to species. The Zoo has identified 39 plant species as suitable for browse. These include seven kinds of bamboo, sugar and Japanese maples, butterfly bush, redbud, birch, tulip tree, kudzu, elm, and willow.
Most of this browse is delivered to animals by keepers, but Darwin the emu has developed his own fast-food approach. He trots alongside the mower when gardener Boyd cuts the grass in his yard. “He likes to get at the grasses as soon as they hit the ground,” says Boyd.
This year, the horticulture team is concentrating on a variety of projects: climbing structures for the apes and Andean bears, a new perch for the bald eagles, fresh seeding in the elephant yard, and rejuvenation of the plantings around the Kids’ Farm and by Uncle Beazley, the life-size fiberglass triceratops across from Lemur Island.
Horticulturists plan the regular maintenance and tweaking of exhibits as carefully as possible, but the rhythms and needs of the animals ultimately shape every decision. This past spring, for instance, the Zoo went into high alert over the possible pregnancy of female panda Mei Xiang. Staff kept her under constant watch.
“With the recent hopeful news, we weren’t allowed in there for some weeks,” says Boyd. As a result, the grasses in the enclosure grew unusually high, giving horticulturists some extra work. Once it became clear that Mei Xiang was not pregnant, gardeners were allowed back into her enclosure. They cleaned out the debris branches, cut the grasses, raked out the grass, and pruned.
There’s another species that creates extra work for the horticulture team: Homo sapiens. “The toughest thing on our plants is the public,” says McLaren. “The happy visitor free-for-all at the Zoo is hard on plant matter.” So the gardeners plant thick masses of flowers along the walkways, an aesthetically pleasing way of saying, “Don’t tread on me.”
Landscaping around the twin lions that flank the Zoo’s Connecticut Avenue entrance poses special challenges. Visitors seeking that special photo opportunity have a penchant for climbing the statues— causing the park’s safety staff to cringe. The gardeners’ solution has been to plant dense, prickly Osmanthus shrubs around the base. Nonetheless, they have still had to replace the shrubs several times within the last year.
This Zoo garden aims to lure hummingbirds. (Jessie Cohen/NZP)
Yet no one’s complaining. The Zoo’s horticulturists tell their stories affectionately, and they clearly love their jobs. “You think you’ve seen it all, and then tomorrow brings another surprise,” says Preston Burke, who’s in charge of all interior exhibits. “The coolest thing,” adds crew leader Craig Rudolph, “is being able to work outside. I have the best view from my office every day.”
That view ranges from exhibits to forest, from humble planting and pruning to major renovations. It’s all part of the varied and valuable work of the horticulture team. “Any plant living, or at one time alive,” says McLaren, “I consider Zoo horticulture.”
—Freelance writer and web producer Valerie May covered the challenges of animal transport in the March-April 2010 issue of Smithsonian Zoogoer.
If you have a comment about Smithsonian Zoogoer magazine, please email it to us.Smithsonian Zoogoer 39(4) 2010. Copyright 2010 Friends of the National Zoo. All rights reserved.