The Tropical House
The Tropical House is closed until further notice for interior redesign
Tropical House Recorded Programs
The Tropical House Collection with
Director Lew Feldman and Curator Holly Forbes
VIEW THE RECORDING
The Famous Corpse Flower: An inside look
with Director Emeritus Paul Licht
VIEW THE RECORDING
The Tropical House Project
Throughout its history, the Tropical House was a challenge to maintain as heating and irrigation systems regularly failed, resulting in plant damage. More recently, glass panes cracked and fell, and engineers advised that the building required renovation and seismic retrofitting. The Tropical House was closed to the public in early 2020.
With the completion of the exterior structural improvements, Garden staff see a new opportunity to renovate and refresh the house’s interior. UCBG Advisory Board member and well-known landscape architect Ron Lutsko is donating his firm’s services to design a modern interior that will engage and educate visitors with an intimate tropical experience. The project includes adding a shade structure to the adjacent patio where small groups gather, and refreshing exterior plantings around the building.
Tropical House Collection
The Garden’s Tropical House provides vital housing for collection specimens (large and small) that require a warm, humid environment to thrive. The plant palette has shifted over time to better accommodate campus teaching needs and the Garden’s interpretation of the wet tropics.
The strongest interpretive and planting theme is ethnobotany. Plants important in human uses (food, fiber, medicine, etc.) continue to be featured. These are arranged by geographic origin, formerly referred to as Old World (Asian/Australasian) and New World (Western Hemisphere), consistent with the general geographic arrangement of the outdoor collections. As we embark on a redesign of the interior, we reflect on this ethnobotanical theme’s variations as it was installed and renovated several times before. Several plants are especially popular, including cacao (chocolate), vanilla, coffee, and pepper. We interpret their usefulness to people while also describing their context in nature.
For example, since 2002, we have learned that the cacao tree (Theobroma cacao) is native only to South America and was distributed by people to Central America and Mexico. Today it is cultivated wherever conditions are favorable near the equator. 70% of the world’s cocoa production is from West African countries. The environmental impacts of farming cacao trees can be mediated by not clearing native tree species, to provide the shade needed by the cacao trees. Compared to traditional orchards, this cultivation technique can reduce the loss of plant and animal biodiversity within the modified plantation. Also, cacao trees need a certain amount of humidity and ground cover plants to support the midges that pollinate their flowers. The midges are also food for birds. The ground cover plant layer hosts other invertebrates, and the canopy hosts animals, epiphytes, and more. We tell this story of growing cacao trees by best practices under a native plant shade canopy to support biodiversity.
In addition to plants with ethnobotanical uses, the Tropical House can support our educational efforts to display and interpret tropical biodiversity hotspots of the world and their conservation issues, now in the context of climate change. This interpretive theme includes iconic plants that may come to mind when thinking about wet tropical locales, like palm trees, lianas, epiphytes, and orchids, some of which are endangered. This assemblage serves our mission of supporting education, research, and conservation.
The contrasting environment of the Tropical House with the rest of the outdoor collections makes it one of our most popular destinations. We look forward to a redesigned interior that will make the most of the limited space to provide an immersive tropical forest experience of heat, humidity, and lush foliage.
Holly Forbes, Curator
Tropical House History
The Tropical House, one of the most popular destinations for Garden visitors, will be 49 years old in 2021. If the gestation period of planning, securing budgets, and construction is included, it is even older. When you enter, you are enveloped in warm moist air and greeted by a wall of greenery, as if you had been transported to the tropics. It is an extraordinary educational venue.
The original structure was completed in 1972, and the plantings installed by 1975. The focus was on economic interest plants and included many popular tropical culinary treats — chocolate, vanilla, coffee, and more.
In 1986, the Tropical House underwent its first renovation. The drainage and heating systems had deteriorated, and the compacted soil needed replacing. Renovations completed by late 1987 included removing the cement pool from the center of the building. A fiberglass pool replaced it with volcanic rocks above and water dripping down its face, providing suitable habitat for a variety of epiphytes. The new soil was warmed by heated water in tubes buried six inches below the surface, and pavers replaced the gravel flooring. The plants were arranged with those from the western hemisphere on right and those from the eastern hemisphere on the left.
An enormously popular program, first presented in 1989, was “Rainforest Rap.” Given during the winter, the tour emphasized ecology and conservation. “Rainforest Rap” evolved into “Tropical Treasures,” which emphasized the uses of tropical plants. The new iteration included more information about indigenous peoples as well as in-house displays of tropical foods such as mangos, pineapple, coconut, chocolate chips, and tropical juices.
Without question, the most popular plant celebrity is the titan arum (Amorphophallus titanum). When it blooms, which is infrequent, one would think that a Hollywood movie star had come to the Garden. Visitor numbers typically triple when one of these remarkable plants produces an inflorescence, which only lasts a few days. Sometimes the lines to visit it stretch to the entrance gate. A Garden tradition is to name them: Trudy was the first one, followed by Titania, Odora, Odoardo, Tiny Titan, Maladora, and Little Stinker. The first to bloom was Trudy in 2005, and seven others had bloomed by 2010. Trudy must love the limelight: she bloomed in 2005 at ten, then again in 2009, and again in 2015. What a performer!
The Tropical House again began to show its age; both the building and its plants were beginning to grow old. In 1998 the house was closed to the public because several trees had grown so tall that they broke ceiling glass! In September 2018, it was closed because of broken glass in the roof. The repairs were made in a timely fashion, and the Tropical House reopened in November. This was especially appreciated because the house is a much-loved destination during the winter with its excellent heat and abundant foliage.
Garden staff recognized that the Tropical House needed a major overhaul. Thus, in late 2018, plans were initiated for its renovation. By March 2019, the plans had been submitted to campus for approval. The first phase was to reskin the entire building with polycarbonate material to replace the glass. This material does not need whitewashing and is twin-walled for greater insulation; other project elements included earthquake retrofitting and a new heating system to replace the ancient heaters. By August of 2020 the reskinning and earthquake retrofitting were in process. The next step is the redesign of the interior to enhance the visitor experience.
Mara Melandry, Volunteer
One of the most famous plants in this collection is the titan arum (Amorphophallus titanum). This plant is native to the rainforests of Sumatra, Indonesia. They produce one of the world’s largest flowering structures to lure insects with the illusion of decay—having both the appearance and odor of rotting flesh; hence the plant’s common name, “corpse flower.”
Titan arums produce only one leaf at a time, but they’re one of the world’s largest leaves. A young titan arum produces a relatively small leaf, but each leaf it produces is bigger than the previous leaf, eventually reaching 3 to 5 meters (10–15 ft) tall—as large as a small tree! The leaf photosynthesizes, making sugars that are stored as starch in a swollen, underground stem (corm). The corm must reach at least 14 kg (30 pounds) before blooming may occur; corms have been known to weigh up to 90 kg (200 pounds). A leaf withers after about 16 months and the titan arum goes completely dormant for four months or longer. When it next sprouts, the corm will produce either another single leaf or a bloom. Because flowering takes so much energy, the corm produces one leaf after another for years before blooming again. It’s typically 6–7 years before a titan arum blooms for the first time, but it may take much longer. The flowering structure may take months to form, but only remains open for a day or two while pollination may occur. Without pollination, the whole structure collapses and the cycle repeats.
A titan arum bloom appears to be the world’s largest flower, but it is actually a stalk of many flowers (an inflorescence). Hundreds of tiny, petal-less flowers are clustered at the base of the yellowish-gray, phallus-like structure (spadix) that can grow to be over 3 meters (9 ft) tall. The flowers are hidden from view by a large, pleated, skirt-like covering (spathe) that is light-green and speckled cream on the outside and deep maroon on the inside. If pollination takes place, the spadix remains firm while the fruits develop over a period of months.
In October 2018, a corpse flower known as Maladora opened at the UC Botanical Garden. Below is a video by PBS explaining the adaptations of the plant to attract pollinators and showing the flower’s bloom cycle.