PHOENIX – Hundreds of green, orange and blue butterflies fluttered about the Desert Botanical Garden’s special exhibit this spring. The garden featured 14 species, but it’s the iconic monarch butterfly that has captured the attention of garden officials.
Experts link the loss of milkweed to the dramatic decline in the monarch population – nearly 90 percent in the past two decades. To counteract the drop, the garden is promoting the planting of milkweed native to Arizona.They want to help save the species, and they’re paying close attention to the stalky green weed the iconic monarch butterfly must have to survive.
“From millions, to a million or less – and that’s because the milkweed is gone,” said John Meier, a volunteer at the garden.
During the spring, monarchs migrate thousands of miles through the United States to Canada, making stops on the way from their winter roost in Mexico.
Kim Pegram, an insect ecologist and exhibit specialist at the garden, said a female monarch “will seek out milkweed to lay her eggs on because it’s the only thing her caterpillars can eat. If they don’t have milkweed plants, they don’t survive.”
Milkweed has declined because of agricultural activities, development and the increased use of herbicides, she said.
So far, the program has seen success. Officials said the number of monarch butterflies and milkweed species in Arizona has increased, according to garden’s website.
Although the botanical garden’s initiative exclusively tracks the monarch population, Pegram said it’s possible other butterfly species have declined as well. Increased milkweed habitat also can benefit other pollinators, including honey bees, she said.
The Roosevelt Elementary School District in Phoenix is part of the Great Milkweed Grow Out.
Gail Cochrane, the manager of the Brooks Community School Greenhouse, oversees one of six milkweed pollinator gardens planted by the botanical garden at schools and parks.
The greenhouse expands lessons in science, technology, engineering, arts and mathematics taught in K-8 schools, and it typically hosts two field trips a month with 19 Phoenix schools. The project teaches youngsters the vital role milkweed plays in a monarch butterfly’s life cycle.
“The monarch butterfly is so charismatic that pretty much every student knows what a monarch butterfly is,” Cochrane said. “Because of that personal relationship and recognition of the monarch, they connect with the plant.”
The garden collects seeds across the state. It donates some to nonprofits and also sells milkweed to the public. The garden’s website provides tips on how to find and care for milkweed.
– Cronkite News video by Melina Zuñiga
This story is part of Elemental: Covering Sustainability, a new multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal.