Is desert landscaping sustainable?
Desert landscaping, as a choice for beautifying residential properties in cities, is going to be around for a short period of time, predicts Chris A. Martin, professor of horticulture at Arizona State University.
“Overall, we’ve shown we don’t know how to properly manage desert landscapes in large cities,” said Martin, who is head of faculty for science and mathematics in the College of Letters and Sciences at ASU’s Polytechnic campus.
The mismanagement of desert plants and xeriscapes was alluded to in a recent New York Times feature story, in which professor Martin offered comment.
The Feb. 4 article, “For the Prickliest Patients, A Doctor Makes House Calls,” profiled the work of Phoenix "cactus doctor" Rilée Leblanc, who works to save ailing desert cacti, and his business is in demand.
The story pointed out that as low-water-use plants and desert landscaping have grown more popular with desert dwellers, knowledge of how to care for xeriscapes has not kept pace.
“We want the desert landscape to look lush, and we want it to look lush tomorrow,” says Martin in the story, referring to the overwatering that is often part of mismanagement.
“But desert plants are evolved to survive with little water,” he explains. “They are uniquely adapted to use every drop of water when it’s available to them. You bring that ability into a city where lawns are watered and these plants grow like crazy, flower very quickly – their systems and natural cycles are sent into overdrive, their health degrades and they die relatively young.”
All that growth leads, inevitably, to over-pruning.
“Desert plants out in their native habitats grow in shapes much like giant toadstools,” Martin said. “They grow as domes with a protective canopy that wants to go down all the way to the ground. But people want to trim them in their yards like they would an elm tree in another climate. It’s a recipe for disaster – pruning is a very wounding process for a tree.”
He notes that landscape mismanagement also brings discomfort to humans, in the form of allergies from pollens in plants like ambrosia (ragweed) or from the over-flowering that comes with over-watering. Leaf debris of the mesquite and palo verde trees also cause dermal sensitivities.
“If someone were to appoint me landscape czar, I’d ban leaf blowers,” he said.
What landscaping advice does Martin have for desert residents?
“Whatever landscape style you choose, educate yourself to manage it properly. Regardless of your design motif, adjust your management strategies to optimize the design’s intentions, and take into account all the microenvironments of your yard before you plant," he said. “The one-size-fits-all approach, where all plants are watered and pruned the same, will fail. In our degree programs and courses in sustainable horticulture at the Polytechnic campus, we train individuals to understand the nuances present in a diverse landscape – and how to manage them.”
Martin is a landscape horticulturist and ecosystem-stress plant physiologist whose interest is urban landscape sustainability. He is also a senior sustainability scientist in ASU’s Julie Ann Wrigley Global Institute of Sustainability and serves as a technical adviser for the national Sustainable Sites Initiative, and has served on the Community Forestry Committee to the Governor’s Arizona Forest Health Council.