College of Liberal Arts and Sciences at Iowa State University

High level gardening

Steve Mahoney oversees one of the Midwest's largest plant collectins atop Bessey Hall
If you want to find the world's best collection of cotton don't go to the deep South. Mississippi, Alabama and Georgia have nothing on Iowa State.

Looking for many different types of cactus? You might think of going to New Mexico or Arizona but not Ames. And if bamboo is more to your liking, China seems like the obvious choice.

Obvious maybe, but if an individual would like to find the finest collection of bamboo, cotton or even cactus you just have to venture to the top floor of Bessey Hall and tour the botany department's greenhouse - the Pohl Conservatory.

"The bamboo collection that Lynn Clark (associate professor of botany) has established here at Iowa State doesn't exist anywhere else in the world," said Jonathan Wendel, professor of botany. "And there is certainly no other collection that is superior to the cactus collection that Rob Wallace (associate professor of botany) has assembled."

Wendel himself has achieved a similar collection of cotton in the Pohl Conservatory. The world's wild relatives of cultivated cotton are housed on campus, including cotton species from Australia, Ethiopia, Yemen, Mexico and the Galapagos Islands.

The Pohl Conservatory is named for former Iowa State botany professor Richard Pohl, who established the original collection. Pohl was famous within the botany department for bringing back seeds from the four corners of the earth.

The 12,000-square foot facility contains 18 rooms and houses the University plant collection, many derived from Pohl's seeds.

It is the second largest greenhouse collection of plant species west of the Mississippi, illustrating a wide range of families and current materials being grown for classroom instruction.

Steve Mahoney, greenhouse manager, said the collection contains more than 800 species of plants. Wendel goes as far as to say that only the Missouri Botanical Gardens in St. Louis can rival what is available to students and faculty atop Bessey Hall.

"It's an astonishing collection of botanical matter," he said.

A few plants in the Pohl Conservatory collection even have become extinct in nature, but have been brought back to life after being grown in the Bessey greenhouse. Seeds from these plants or the plants themselves have been sent to other gardens.

The assimilation of plants in Bessey is what Wendel calls a "living collection." "When you have a living collection, it's a never-ending task to maintain that collection," he said.

That task was made easier in the late '90s with a renovation project funded in part by a National Science Foundation (NSF) grant and funding from the College of Liberal Arts and Sciences. The $750,000 project was the first major renovation to the greenhouse since it was first constructed in the late 1960s.

Mahoney said the project involved reglazing the greenhouse windows, updating the heating, ventilation and air conditioning system as well as electrical and plumbing. Prior to the renovation, controlling the temperature was an extremely difficult task.

"It was hit and miss," Mahoney said. "The ventilation system was all manual and we had to do it room by room."

Now Mahoney can control the temperature in each of the 18 individual rooms through a computer in his office. Six mini-computers are placed throughout the facility. Additional space was also achieved for teaching and research efforts when cooling towers were removed from the Bessey roof.

"We have a much more energy efficient greenhouse," Mahoney said. "A greenhouse that is much more efficient in several ways. "Because of the changes, the plant growth in the greenhouse has increased substantially."

Despite the large collection, there are still a few plants that Wendel says are difficult to grow atop Bessey Hall. It's typically easier to grow plants from the tropics for instance than those that require a winter season.

"While we can duplicate the tropics in the greenhouse, it's very difficult to mimic winter," he said.

In addition to serving as a conservatory of plants, the Bessey greenhouse has two other functions. Just as important Wendel says is the research component of the facility. Space is provided to faculty and graduate students for research, including a number of small isolation greenhouses for individual experiments.

Teaching is another important aspect of the greenhouse. Botany students utilize the space for classes throughout their course of study. Wendel says the greenhouse and its vast collection of plants is important for undergraduates and graduate students.

"You can't learn plants from a book," he said. "Unless you're out there looking and touching the plants it really isn't the same thing.

"The greenhouse provides a more lasting impression for a student. There they can walk under a chocolate plant. That's so much better than looking at the same plant in a book or even on a CD-ROM."