Melina Zuñiga

Friday, May 18, 2018

In the weeds: Desert Botanical Garden promotes milkweed to save threatened monarch butterfly

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.

Named after the green mineral because of its vibrant colors, the malachite butterfly’s bright wingspan is approximately two to four inches across. (Photo by Melina Zuniga/Cronkite News)

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.

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.

“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.”

The Phoenix Desert Botanical Garden leases three tables from the Roosevelt Center of Sustainability exclusively for the growth of the Arizona Milkweed plant. (Photo by Melina Zuniga/Cronkite News)

[2up_image-standard source1=”” caption1=”The life cycle of the butterfly consists of four stages. Monarchs rely on milkweed plants to complete their life cycle because eggs are laid on milkweed, which is the larvae’s only food source. (Photo by Melina Zuniga/Cronkite News)” source2=”” caption2=”As part of their initiative, the Phoenix Desert Botanical Garden sells one of the 29 species of milkweed native to Arizona in the gift shop. (Photo by Melina Zuniga/Cronkite News)”]

Milkweed has declined because of agricultural activities, development and the increased use of herbicides, she said.

To bolster the monarch population, the Desert Botanical Garden a few years ago established the Great Milkweed Grow Out . The program, which includes partnerships with schools throughout the state, aims to restore lost habitat by planting native milkweed.

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.

Gail Cochrane, manager of Roosevelt Center of Sustainability in the Roosevelt School District, said students who visit the greenhouse are taught about milkweed and its role in the monarch’s life cycle. (Photo by Melina Zuniga/Cronkite News)

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 Nicole Randock

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.

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