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In views on native vs exotic plants, Phoenix and Tucson are ‘100 miles and 100 years’ apart {With ASNS slide show}

 

TUCSON — Before going to work as the assistant dean of the College of Pharmacy at the University of Arizona, Richard Wiedhopf wakes up just a little bit earlier than he otherwise would need to —  to tend to the saguaro and barrel cacti in his yard, while admiring the sunrise over the Arizona desert. Also the president of the Tucson Cactus & Succulent Society, Wiedhopf is among a growing number of Tucson residents who actively seek to preserve the natural landscape of the Sonoran desert and the native plants it nourishes.

Although the Sonoran Desert is home to about 4,000 native-plant species, urban development has led to a greater need for their preservation and sustainability. But with a difference in the availability of water and sometimes different cultural attitudes between desert cities like Tucson and Phoenix, the actual Sonoran plant life can vary widely, from lawns lush and green with grasses that are exotic to the desert, to native plants that know how to live naturally in an arid climate.

“Between Phoenix and Tucson, two different approaches in regards to landscaping can be seen through the exotic flowers and well-kept lawns of Phoenix, to the abundance of saguaros and other desert plants in Tucson,” said Kathryn Hahne-Ramirez, a horticulture assistant agent with SmartScape, a water landscaping conservation and education service of the University of Arizona and Pima County Cooperative Extension.

“The main difference in Phoenix is that it started as, and still remains to be, an oasis environment. Maintaining this idea of an oasis in the desert is part of the cultural identity — that’s a part of what makes Phoenix,” she said.

In contrast to the lushness of Phoenix, Tucson adjusted earlier to the scarcity of water needed for daily living and landscaping purposes. Being more of a metropolitan city compared to Tucson, Phoenix has always been seen as an oasis in the desert and its inhabitants have worked to maintain the landscape so it may reflect this ideal.

“Since about half of the water used in Tucson residences is used for landscaping purposes and there is a shortage of water here in the desert, restrictions on water usage and the type of plants that can be planted were installed,” Hahne-Ramirez said. “These plant and water restrictions would then determine the plant pallet for Tucson and lead to the slow transition from high water use plants to those that can survive in the desert and that do not need much water.”

Saguaro National Park, Tucson (ASNS Photo)

Saguaro National Park, Tucson (ASNS Photo)


With the shift from high-water-use plants to plants that are native or adaptable to the desert, the Tucson landscape has become a true model of the Sonoran Desert.

“People from all over come to Tucson to experience the desert and the native plants that make up its natural landscape,” said Wiedhopf. “Saguaros and other kinds of cacti and succulents are native to this land and many people in the community are invested in keeping them alive.”

Aside from their aesthetic appeal, native plants have an important role in how living organisms interact with one another and greatly influence the well being of the human environment.

“Native plants help sustain our environment and keep the balance of nature,” said George Ferguson, the collections manager of the University of Arizona Herbarium, which houses the world’s largest collection of plants from Arizona and Sonora, Mexico.  “Man-made changes in the environment such as increased water usage and construction development may seem small but can greatly affect the survival of native plants and as a result, affect the survival of other birds and fish in the desert.”

Obviously, the expansion of development into desert habitats has been the key factor in the destruction of native plants, but ironically the resulting proximity of desert-landscape lovers to that natural environment is a driving factor in recognition that this plant environment is threatened.

“There are so many different species of plants here in Arizona, and yet there are some that are on the verge of extinction,” Ferguson. “In places such as Phoenix where much development occurs, disrupting the land will permanently change the soil and will alter the plant’s ability to grow and adapt to their new environment.”

Compared to Phoenix, far more-conscious efforts are being made in Tucson to value and preserve the native plant environment.

“Driving around Phoenix, I see desert landscaping — but I also see so many green lawns, which doesn’t make sense since we live in a desert and water resources are limited,” said Wiedhopf. “Tucson is about 100 miles and 100 years different than Phoenix, as there is less water here and in turn that attracts a more environment-conscious lifestyle.”

In an attempt to create a more realistic desert landscape, and to better sustain the plants on the University of Arizona campus, Dr. Tanya Quist, an assistant professor and director of the university Campus Arboretum, is working with others to introduce a mix of plants, including some non-native ones that are easily adaptable to the harsh desert environment, where they can provide things like shade.

“Arizona has almost every environmental stress there is such has intense heat and lack of water,” Quist said. “My aim with the Campus Arboretum is to create a more sustainable desert landscape here at the university that decreases the input of water usage, pesticides and manual labor put in to plant maintenance, while increasing the amount of shade, procession of carbon and real-estate value that can be produced.”

Quist is currently working with the U.A. Campus Arboretum to implement more natural practices of maintaining campus plants and is in the process of putting together a list of plants deemed to be more sustainable. “Native plants are important here in Arizona as they have learned to evolve with the environment over time and require less maintenance due to their adaptability to desert conditions,” Quist said.

“In order to conserve resources and manage a more sustainable landscape, we are working to incorporate a mix of native and non-native plants that may be better suited to survive in certain areas around campus,” she said.

In partnership with Wiedhopf, Quist and other members of the Tucson Cactus & Succulent Society and the UA Campus Arboretum are working to maintain and add to the Cactus Garden on the campus Mall to better reflect the natural Sonoran Desert ecosystem.

“Water is limited here and the native cacti within the historical Cactus Garden are great examples of what a sustainable desert landscape should look like,” Quist said.
The familiar Cactus Garden, with many native species of cacti and other various trees and plants, was built in 1891. Having fought to keep the garden from being bulldozed in the 90s, members of the Tucson Cactus & Succulent Society continue to rescue different cacti and succulents for transfer to the garden.

“We felt very strongly about the native plants displayed in the Cactus Garden, as they are historical examples of what this land should look like,” Wiedhopf said. “We are still rescuing these plants and even donated four of our Queen of the Night cacti, a rare species of native cactus, to be planted in the Cactus Garden.”

Along with contributing to the visual landscape, native plants are important to Southwest agriculture because they can be harvested and cultivated for production. “The native people of the region have been using these desert plants, which can still be utilized today, for various remedies and purposes,” Ferguson said. “Plants like jojoba [a native shrub grown in Tucson and other desert regions in the Southwest] are used to make many store-bought lotions, whereas the bean pods of Palo Verde trees can be harvested and eaten.”

Wiedhophf noted that saguaro and some other characteristic plants “can’t be seen anywhere else,” and added:  “If we live in the desert, it is our job to preserve the plants and wildlife that are a part our environment, so it continues to look like the desert.”

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