Monarch butterfly advocate raises awareness of growing milkweed

It was a school field trip during his childhood in Southern California that introduced Brad Grimm to the majesty of the monarch butterfly.

When his class took the half-hour trip to Natural Bridges State Beach, Grimm took in a view he wouldn’t soon forget. Natural Bridges, located in Santa Cruz, Calif., has become known to visitors as a place where monarchs spend their winters clustering in the park’s eucalyptus trees.

“There were hundreds of thousands of monarchs there,” he said. “It left a pretty big impression on me.”

Fast forward to the early 2000s, when Grimm returned to the park with his then-girlfriend to show her the monarchs, and found a much smaller population.

“The naturalist at the park said the numbers were significantly down,” Grimm said. “That’s when I started researching things that would help the monarch butterfly.”

A real-life scavenger hunt

Milkweed plants are essential habitat for monarch butterflies. Adult butterflies lay their eggs on the plants, and when the caterpillars hatch, milkweed is their sole food source.

As Grimm began working on a website to gather information on growing milkweed, he began seeking out milkweed plants growing around his own community. He found it in parks, along sidewalks, in stormwater ditches and at truck stops.

Grimm started an organization page for his website on Plants Map to track the milkweed he found growing locally in the area. On the page, he keeps track of the condition of this plant that many still consider a weed—perhaps unaware of its importance to the monarch.

In an entry on milkweed found growing at a local marina, Grimm followed up to report that groundskeepers had subsequently pulled out all of the milkweed as part of a cleanup effort.

“It was very disappointing,” he wrote. “The roots will re-grow next year. But without education about the plant’s purpose, it will be pulled up again next year. It’s my goal to provide that education over the next year.”

Grimm hopes to build a network of fellow milkweed enthusiasts who can join him in tracking native milkweed varieties, and help educate the public about the plant’s importance.

Tracking a habitat

Grimm’s efforts have culminated on his website, The website grew out of Grimm’s efforts to find information on how to increase the availability of milkweed—and specifically which milkweed species were native to different parts of the United States.

“I started trying to discover what types of milkweed plants were grown in Nevada, where I had just moved,” he said. “The resources were slim, so I set about developing a website to help people who are kind of at the same step that I was at the time, to locate native milkweed plants to where they lived in the U.S.”

Like many gardeners, Grimm had no problem finding tropical milkweed species when he searched local garden centers.

Milkweed has become more popular as awareness has spread due to the monarch’s plight. However, some research has suggested that planting tropical milkweed in gardens all over the U.S. poses several issues, including the potential for parasites. Scientists have begun to encourage people to also seek out native varieties to grow.

That’s just what Grimm is trying to do on his website, which includes a list of all of the milkweed varieties he’s researched. He is also working to build a map that would allow visitors to click on their state to determine what varieties are native to their area.

Becoming a source for milkweed

Grimm also has a podcast about milkweed where he shares some of the tips and tricks he has learned as he’s gotten to know the plant.

Growing native milkweed varieties has taught him how hard it is to start this plant from seed. His advice: treat it like a wildflower.

“Plant it in the fall when plants are going dormant, let the seed spend the winter in the soil, then the seed is prepared to grow in the springtime,” he said. “A little bit of neglect can actually improve its germination rate.”

Those working with the plant for the first time should also be aware that its white sap can be a hazard. If you are handing the plant, wear disposable gloves to avoid transferring the sap to the eyes, where it can cause severe irritation and damage.

On the fun side, though, Grimm thinks more people should know that milkweed blooms are a beautiful reward for propagating this plant that plays an important role in the ecosystem.

“For a plant that people are trying to eradicate in farm fields, it actually puts out profuse blooms that come in colors from orange to pink to red,” he said.

A rewarding pursuit

His interest in monarchs and milkweed has helped Grimm develop a better appreciation for wildlife of all kinds. He documents his home garden on his personal Plants Map page, and enjoys watching bugs, birds and even beneficial snakes that come and go as the season progresses.

And as for the monarch population back at Natural Bridges State Beach, Grimm has returned twice in the past few years with his wife to revisit the site that first sparked his interest.

He was heartened on recent visits to learn that populations were beginning to stabilize, and he recommends a visit to a place where monarchs spend their winter months to anyone with an interest in the species.

“If you’re watching the cluster as the temperature starts to push past 55 degrees, you tend to see almost all the butterflies simultaneously begin to open their wings and disperse,” he said. “It’s a really magical feeling.”

To learn more, follow/connect with Brad Grimm at Grow Milkweed Plants on Plants Map