Groundbreaking Design at the Botanic Gardens

One of Denver's architectural gems remains a cutting-edge design, 50 years after it was built.

Illustration by Hand: Original drawing of the exterior view of the conservatory. Image courtesy of Denver Botanic Gardens.

A building that is as timeless as it is of its time, the Boettcher Memorial Tropical Conservatory at Denver Botanic Gardens has stood as one of Denver’s architectural treasures since its completion in 1966. Remarkably, only seven years after being built, the City designated it an architectural landmark. Determining if a design will endure and become a classic can take 30 to 50 years. Clearly, its design was quickly recognized for the work of art it is.

Designed by legendary Denver architects Victor Hornbein and Ed White, the 11,500-square-foot structure took two years to build and is the only conservatory in the United States made of cast-in-place concrete. Rooted in history, the structure was, nonetheless, aspirational in its innovative concept.

Illustration by Hand: Original drawing of the interior view of the conservatory. Image courtesy of Denver Botanic Gardens.

While the structure gives a nod to the light and airy soaring vaults of Gothic cathedrals, the Conservatory remains thoroughly modern. It was a radical design that demanded innovative, experimental construction.

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Prior to designing the Conservatory, Hornbein was known as the designer of Mayan Theater while at another firm. He, however, viewed Beaux Arts as too ornamental and decorative. His leanings definitely were modern.

A visit to some of Frank Lloyd Wright’s homes in Chicago only strengthened Hornbein’s conviction that the visionary’s organic modernism was the future. He embraced Wright’s principles: using simplicity of design, natural color and finishes, and the inherent aesthetic nature of materials, among others.

Futuristic Design: The rooftop of the auditorium building echoes the design of the Boettcher Memorial Tropical Conservatory. Photo courtesy of Denver Botanic Gardens.

Hornbein established his own firm where he carried out Wright’s philosophy of organic modernism. In 1960, he joined forces with East High School graduate White, a preservationist and a modernist.

White helped establish the Denver Landmark Preservation Commission in 1966, then served on the board for 27 years, saving many Denver buildings from the wrecking ball.

White attended Columbia University, where he became close friends with dropout and author Jack Kerouac, poet Allen Ginsberg, and Allan Temko, a classmate who in 1990 won a Pulitzer Prize for architectural criticism. White, of the Beat Generation, embraced modern aesthetics.

The most enduring outcome of the Hornbein and White collaboration was also the most challenging.

Photo courtesy of Denver Botanic Gardens.

The Boettcher Foundation funded the Conservatory and also owned Ideal Cement. Therefore, the use of concrete in the structure seemed to be a very good idea. In the initial design, the building had straight ends and a barrel vault, but architects added the hip vaults at the ends, which created an inverted catenary arch and kept the beams a reasonable size. The architects chose plexiglass pyramids for the structure and formed panels at an angle that would direct condensation to the edges of each panel’s concrete frame, rather than drip on visitors. The panels were slightly different sizes, so each panel was sized to fit its place in the structure.

“It was our responsibility to try to figure out if we could do it in as a cast-in-place concrete structure,” Richard Breaker, the builder on the project, told Denver Botanic Gardens. “My first thing that I did was to build a sample panel out in our backyard. It took me the longest time to come up with this, but we had to provide a means for our workmen to actually get up onto this surface and do the forming and the installation of all the reinforcing steel and the eventual pouring of the concrete.”

White, upon the fiftieth anniversary of the building, said, “It seems it’s a building that never grows old.”