A Second Flowering

By: James Henrich Scot Medbury

James E Henrich is curator of living collections at Los Angeles County Arboretum & Botanic Garden, having previously worked at…

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A panoramic view of the historic Conservatory of Flowers in its Victorian setting in San Francisco’s Golden Gate Park. Photographs by Kevin Frest, except as noted

A panoramic view of the historic Conservatory of Flowers in its Victorian setting in San Francisco’s Golden Gate Park. Photographs by Kevin Frest, except as noted

The recently reopened Conservatory of Flowers celebrates its 125th birthday in 2004—the oldest public conservatory in North America.

The jewel of Golden Gate Park is back. Eight years after a Pacific storm, driven by one hundred mile-per-hour winds, devastated San Francisco’s historic Conservatory of Flowers, the graceful wood-and-glass structure is as good as new, having been painstakingly restored and thoroughly outfitted with new tropical displays. Since reopening in September 2003, more than 150,000 visitors have explored the jungle inside the landmark greenhouse. While it may be the romance of the ornate Victorian architecture that attracts them at first, it is the collection of extraordinary plants inside that people remember. Old favorites, such the century-old imperial philodendron under the Conservatory dome, continue to amaze visitors, as does a host of newly acquired plants drawn from the far corners of the world’s tropics. The challenge of assembling and presenting this plant collection serves as a reminder that, with both indoor and outdoor gardens, nothing is as easy as it seems.

Unrevealed Provenance

Received wisdom on the origins of the Conservatory of Flowers has proven long on legend and short on fact. The building was found as a boxed kit of wood and glass among the effects of wealthy San Franciscan James Lick upon his death in 1876. No primary evidence seems to have survived to explain when or where Lick acquired the conservatory; whatever documentation might have existed likely burned in the fire that followed the 1906 San Francisco earthquake. The much-repeated story that the Conservatory was modeled after one at Kew is simply odd (the structure looks nothing like either the Palm House or the Temperate House there), while the assertion that the kit came around Cape Horn from Europe or the East has proven impossible to substantiate. The bulk of the physical evidence suggests a northern California manufacture, in part because the Conservatory’s wooden frame was fashioned from locally abundant coast redwood. However, redwood lumber also was exported in the 1860s and 1870s to the eastern US and to Europe for use in greenhouse construction, so the possibility does exist that the kit originated elsewhere.

The Conservatory’s purchase from Lick’s estate is well documented, as is its donation to Golden Gate Park, where the building was erected on the site set aside for a conservatory in the Park’s original 1872 plan. Opened in 1879, the Conservatory of Flowers went on to survive two fires and undergo several major structural repairs over the next twelve decades. Today it is the oldest extant public conservatory in North America, and is listed on city, state, and national registers of historic places. It also is a civil engineering landmark, so designated because it serves as a rare example of a Victorian-era prefabricated building.

Under the dome, the Lowland Tropics gallery is filled with bold foliage plants, including the hundred-year-old imperial philodendron (Philodendron speciosum) barely visible at top left; red crownshafts mark the sealing wax palms (Cyrtostachys renda). Sunlight shining through colored glass panels below the dome splash the foliage with gold, orange, and blue highlights

Under the dome, the Lowland Tropics gallery is filled with bold foliage plants, including the hundred-year-old imperial philodendron (Philodendron speciosum) barely visible at top left; red crownshafts mark the sealing wax palms (Cyrtostachys renda). Sunlight shining through colored glass panels below the dome splash the foliage with gold, orange, and blue highlights

Venerable Specimens

The 1995 windstorm collapsed entire sections of the Conservatory, shattering hundreds of windowpanes and embedding shards of glass in the trunks of mature palms. After several years of research, design, and fundraising (led by Friends of Recreation and Parks),  re-construction began on the building’s west wing in the spring 2000. Over the next three years, the Conservatory was completely dismantled in phases, a new foundation was poured, and the structure was re-assembled and seismically strengthened using more than fifty percent of the original wood. The construction strategy necessitated that all the plants growing in the loose, sandy soil inside the Conservatory be dug up and temporarily relocated. Two enormous cycads-Dioon spinulosum and Zamia lindenii-which first appeared on the Conservatory’s plant inventory in the early decades of the twentieth century, presented particular relocation challenges because of their size and weight. These specimens were boxed in place and lifted up and out of their pits, using a cable dropped through the roof from a gigantic crane staged outside the glasshouse. Moving the old cycads allowed them to be displayed to better advantage when they were replanted and freed their original locations for new exhibits. Both plants, originally housed in one of the two east wing galleries, found a new home in the Lowland Tropics exhibit under the dome.

One plant could not be dug: the signature imperial philodendron (Philodendron speciosum), acquired around 1901. A gangly, thirty-five-foot tall vine that had attached itself securely to the building, the philodendron would simply fall in a heap if removal was attempted. Instead, scaffolding was erected around the plant, two layers of plastic sheeting were shrink-wrapped around the scaffolding, and heat, light, ventilation, and mist were provided inside the enclosure. Shivering on the edge of the North American continent (the Conservatory is less than three miles from the ocean) the philodendron spent the winter of 2002-03 inside its plastic tent while the dome was rebuilt. The environmental control system was programmed to telephone staff if the temperature inside the enclosure dropped below 60°F; a back-up generator and auxiliary heaters were on hand in the event a catastrophic freeze should occur (temperatures had dropped to 24°F for four days outside the Conservatory during the infamous 1990 freeze!). The winter proved a mild one, however, and the philodendron emerged as robust as ever, braced by new steel supports.

Another old-timer at the Conservatory is a pygmy date palm (Phoenix roebelinii) that was first displayed at San Francisco’s 1915 Panama-Pacific International Exhibition. No longer a pygmy, this twisted sixteen-foot specimen waited out the construction inside the philodendron enclosure along with the two cycads. A few other tall palms, including two spiny, stilt-root Verschaffeltia splendida palm from the Seychelles Islands, were packed off to the tall greenhouses of a commercial interior-plant maintenance company, which kindly loaned greenhouse space during the dome’s reconstruction. Most of the other plants were squeezed into support greenhouses behind the Conservatory, or were moved into the west wing of the Conservatory once it was up and running.

Diverse Environments

One of the goals of the Conservatory exhibition program was to capitalize on the five different climate chambers, creating variations not only in temperature and humidity but also in visual character. Because the tropical philodendron remained in place under the dome, it was essential that a program of warm temperatures and high humidity continue there. The dome became the Lowland Tropics gallery, focused on the amazing diversity of plants from the pan-tropical lowlands, including species from some of the world’s disappearing tropical rainforests. Palms have a strong presence in the dome, and the collection includes an unusual species of royal palm (Roystonea borinqueana) and a grouping of sixteen-foot-tall sealing-wax palms (Cyrtostachys renda) with bright-red crownshafts.

Dracula venifica, one of the high-elevation Pleurothallid orchids that might be seen flowering on one of the artificial trees in the Highland Tropics gallery. Photograph by Ron Parsons

Dracula venifica, one of the high-elevation Pleurothallid orchids that might be seen flowering on one of the artificial trees in the Highland Tropics gallery. Photograph by Ron Parsons

The best plant collection at the Conservatory of Flowers is one of higher-elevation tropical orchids. Placed taxonomically in the Pleurothallid group, which includes the genera Dracula, Masdevallia, Restrepia, and Pleurothallis, and hailing primarily from cool, mid-elevation forests of the Andes Mountains in Ecuador, Colombia, and Peru, the collection has thrived in foggy Golden Gate Park, where the average monthly temperatures in January and June differ by only 10° F. The Pleuro-thallid collection was assembled by a former Conservatory director, George Marcopulos, who won dozens of awards for the Conservatory from the American Orchid Society. From this orchid collection, the concept for the Highland Tropics gallery was born, with the idea being to operate one gallery at much cooler temperatures and feature plants from tropical mountains.

Rising from a sunken garden, the artificial trees are festooned with orchids, bromeliads, and ferns in the Highland Tropics gallery. Sculptural pieces, such as the art-metal orchid on the railing, embellish each of the galleries

Rising from a sunken garden, the artificial trees are festooned with orchids, bromeliads, and ferns in the Highland Tropics gallery. Sculptural pieces, such as the art-metal orchid on the railing, embellish each of the galleries

Tree Sculptures

The considerable value of specimens in the Pleurothallid orchid collection presented an interesting display challenge, since theft was a concern. In addition to providing locked orchid-display cases, exhibit designers from Seattle’s Portico Group created a railed-off, sunken pit from which two types of orchid-bearing tree “sculptures” emerge, allowing the rarest orchids to be displayed well out of visitor reach. One sculpture, with an outer “bark” tooled from epoxy, resembles an old snag and is virtually smothered in orchids and other epiphytes, which have been packed into little fissures and troughs with hidden weep holes for drainage. While a living tree would quickly grow too large for the gallery’s low glass ceiling and an actual dead tree would eventually rot and fall apart, the artificial tree is expected to showcase orchids for decades.

A variety of planted containers, from historic to contemporary, fills the Potted Plants gallery with seasonal color

A variety of planted containers, from historic to contemporary, fills the Potted Plants gallery with seasonal color

The second type of orchid tree could be deployed in other types of garden situations in addition to a conservatory setting. The “trunk” of this tree sculpture is a sealed, galvanized-steel pipe set vertically into a concrete foundation. Branch holders-short pipe sections welded onto a curved base that matches the curvature of the trunk’s pipe-are secured to the trunk using radiator clamps. Various branch angles, orientations and elevations were chosen to simulate a natural branching structure. Into these branch holders are inserted manzanita branches, which have been draped with living orchids secured with fishing line. Finally, all exposed metal pipe is wrapped in stainless-steel poultry mesh stuffed with long-fibered sphagnum moss and then sheathed in dried sheet moss. Voilà-an instant epiphyte-laden tree! The best surprise of the whole endeavor was the discovery that the rehydrated sheet moss had started to grow. As orchids come in and out of flower on the manzanita branches, branches are exchanged with a back-up collection housed in a support greenhouse, making for an ever-changing, year-round display.

The rest of the character of the Highland Tropics gallery is supplied by plants drawn from Chiapas and Guatemala, from New Caledonia, and from the Big Island of Hawaii, where a tall grouping of Hawaiian tree ferns (Cibotium glaucum) was acquired. The New Caledonian plants, the results of a dozen collecting trips to that French overseas territory, include an unidentified species of Meryta, and numerous species of conifers in the genera Agathis and Araucaria. The Highland exhibit is made complete by the sherbet-colored flowers of Vireya rhododendrons propagated at the Strybing Arboretum nursery, and by a diversity of new melastomes and ericads collected by former Arboretum plant collections manager Bian Tan in the mountains of Indonesia, the Philippines, and Vietnam. With the fog system running and the spicy fragrance of exotic cloud-forest plants filling the air, it is easy to imagine oneself on a misty tropical mountaintop when inside the exhibit.

A monarch butterfly feeding on the nectar-rich flowers of butterfly weed (Asclepias sp.) is one of several oversized models showing pollinators and their favorite flowers in “The Birds and the Bees,” the first exhibit in the Special Exhibits gallery. The decorative grillwork in the walkway on the right covers the utilities trench

A monarch butterfly feeding on the nectar-rich flowers of butterfly weed (Asclepias sp.) is one of several oversized models showing pollinators and their favorite flowers in “The Birds and the Bees,” the first exhibit in the Special Exhibits gallery. The decorative grillwork in the walkway on the right covers the utilities trench

The Birds and the Bees

The three remaining Conservatory galleries are devoted to aquatic plants, featuring giant Amazon water lilies (Victoria spp.); seasonal floral displays in a variety of containers; and changing natural history exhibits. The Aquatic Plants gallery has proven the most popular with the public; rushing waterfalls, exquisite stonework, and a diversity of warm-growing orchids, carnivorous plants, and bromeliads make for a rich sensory experience. The opening exhibit in the Special Exhibits gallery, “The Birds and the Bees,” features giant bee, bat, butterfly, and beetle models displayed against colorful mural backdrops and interpretive panels explaining the critical relationships of plants and their pollinators. Live butterflies and moths flit among showy nectar-producing plants to complete the display in this first of many botanically themed exhibitions planned for the space.

Acquiring new plants for the permanent exhibits in the Conservatory proved a complex task due to the restrictions in place to protect California agriculture. With just one opportunity to create a powerful first impression,  large tropical plants were essential and these could only be found in Florida and Hawaii. Considerable effort was expended to negotiate a special permit by which ninety large specimen plants purchased in Florida were allowed to enter the state. These plants first were bare-rooted and repotted in sterile media. They were then grown in Florida for six months and tested for reniform nematodes. The $75,000 gamble paid off; after being quarantined to the Conservatory for a week, the big plants were planted by contractors and are now growing skyward. Other specimens, like the sealing-wax palms, came from Hawaii, and a few from nurseries near San Diego.

In the Aquatic Plants gallery, pools are filled with a  variety of Nymphaea hybrids and other water-loving plants. Overhead, a sculpture in steel and glass by artist Steven Hirt reveals the intricate venation beneath a  giant Amazon water lily leaf (Victoria amazonica)— a plant that made its North American debut at the Conservatory in 1879.

In the Aquatic Plants gallery, pools are filled with a variety of Nymphaea hybrids and other water-loving plants. Overhead, a sculpture in steel and glass by artist Steven Hirt reveals the intricate venation beneath a giant Amazon water lily leaf (Victoria amazonica)—a plant that made its North American debut at the Conservatory in 1879.

Spanning Three Centuries

Climate controls at the Conservatory include components of the original equipment as well as the best of modern technology. The original cast-iron, hand-crank ventilator system remains in place for the ridge vents on the building’s south elevation, while a computer-controlled, motor-driven ventilator system operates vents on the north side. Such a hybrid system seemed sensible in a park where power outages are not infrequent. Another original element that endures is the practice of whitewashing the building to reduce light intensity and control temperature.

The rest of the environmental controls  include a reverse osmosis water-purification system, tempered irrigation water, fertilizer injection, a high-pressure fog system, and even the means to make it rain under the Conservatory’s dome. Utilities are distributed throughout the building in a trench that runs beneath the walkways and is covered by an anodized, cast-aluminum grill with stylized, decorative motifs. In the original building, the utilities were located in the outer beds, concealed beneath planting benches, which required that plants displayed there had to be grown in large pots. The new trench has freed those beds to be luxuriantly planted, thereby creating a more immersive experience for the visitor. The filtration system for the ponds has exceeded all expectations. Pond water is treated using skimmers, settling tanks, styrene-bead biofilters, and ultraviolet-light irradiation, which is doing a good job of controlling algal growth.

An integrated pest management (IPM) program combining sound horticultural practices with mechanical techniques, beneficial insects, and low-toxicity pesticides provides controls for other pests. The most effective biological controls so far are the use of Cryptolaemis beetles for mealy bugs and Encarsia wasps for mites. A small population of geckos is also on hand to hunt for the descendants of a century-old cockroach problem; visitors are told that the charismatic geckos are working lizards, not pets, with an important job to do!

With the building now restored to glory,  running smoothly, and chock-a-block with tropical plants, current plans are focused on enhancing the plant collections, developing further special exhibits and restoring support greenhouses and outbuildings. With strong roots formed in the nineteenth and twentieth centuries, the future of the Conservatory of Flowers, at the outset of the twenty-first, is bright indeed.