Growing Spider Milkweed Seed for Monarch Butterfly

Reader Contribution by Terroir Seeds

The collaborative efforts of Terroir Seeds, The Xerces Society and Painted Lady Vineyard have spent the past 2 years growing southwest native milkweed seed to reintroduce the Spider or Antelope Horns milkweed (Asclepias asperula) to home gardeners, garden centers and native plant nurseries across the southwest. This story is especially poignant right now with the massive declines in Monarch butterfly populations and the resounding recovery push by several conservation groups alongside private citizens, students and scientists.

Milkweed is Critical for Monarchs

The milkweed plant plays a critical role in the monarch life cycle. Each spring Monarchs migrate across the United States, laying eggs on native milkweeds – the only food plants suitable for newly hatched monarch caterpillars. The North American Monarch Conservation Plan recommends planting native milkweed species to restore habitat within the Monarch butterfly’s breeding range. 

For the past 3 years, the total area occupied by overwintering Monarchs in Mexico has dropped by almost 50% each year, continuing a decline that has lasted for the past decade. The severe drought seen across Texas and Northern Mexico has been a large factor, combined with wildfires across the entire southwest. The biggest contributor is simply the loss of land that supports the Monarch’s food source and hatchery – the Milkweed plant. Much of the land has been converted to commercial herbicide tolerant corn and soybean production or developed into housing. Overuse of persistent chemical herbicides and roadside mowing for weed control has also created loss of milkweed habitat and thus reduced Monarch numbers. 

Producing Milkweed Seed

The Xerces Society is working to increase the availability of native milkweed seed and encourage restoration using milkweed in California, the Great Basin, the Southwest, Texas, and Florida. These are important areas of the Monarch’s spring and summer breeding range where few commercial sources of native milkweed seed currently exist. Brianna Borders, Plant Ecologist, contacted us about growing out a small sample of Spider or Antelope milkweed seeds that had been collected in central Arizona to make it commercially available.

Painted Lady Vineyard is a small wine grower in Skull Valley, AZ where Fiona Reid has been growing milkweed and saving the seed for a few years, so she was the perfect fit for our reintroduction project! One of her passions is native plants of the area, with an emphasis on butterfly attractants. The Painted Lady is a beautiful, ephemeral butterfly that happened to visit the vineyard in droves as the initial vines were being planted, thus the name for the vineyard came about. 

A California native plant nursery propagated the seeds into plugs, which were shipped to Painted Lady Vineyard. The tiny milkweed plugs were planted over a long and hot weekend in the middle of June 2012 after much work over many weeks preparing the ground to receive the fragile plugs. There were no financial rewards for any of the volunteers for the hours spent bent over in 100°F heat planting over 2,000 fragile plugs. Many of the people helping were native plant enthusiasts, some were butterfly lovers, but a significant number had were helping see a project to fruition on nothing more than the basis of it is the right thing to do. There were over 320 hours of volunteer labor, not counting Fiona’s time, from start to finish.

Hard Work, but Worth It

In an email to everyone, Fiona said, “It has been an amazing community effort and I have had the pleasure of working with a great group of people, children included. As we began to close in on the finish yesterday I was almost overcome by the understanding that people don’t have to involve themselves in such hard work – sometimes backbreaking work, sometimes knee-breaking work, and always hot work. They could sit at home in the cool, or an office somewhere, and do good for someone else. But none of you did that. You came knowing it was going to be outside in the heat; knowing you would kneel and bend; knowing you would get dust in your nose and eyes; knowing that – as Rachel Carson said – “there is something beyond the bounds of our human existence” that matters. You also know that you won’t get any thanks from the butterflies that find all the little milkweed gardens that will eventually grow from this project.”

She finishes by saying, “We don’t get paid dollars for doing this. What we get is priceless. One day, in many gardens around this area and scattered throughout the southwest, the most ephemeral of creatures – a butterfly – will lay her eggs on the milkweed that has been grown there especially for her, and the stunning caterpillar that emerges will have all the nourishment it needs right there. Soon thereafter, through the miracle of metamorphosis, a monarch butterfly will continue the northward journey. We may only get a fleeting glimpse of this whole cycle, but that’s OK – we just need, it seems, to know that we are part of a bigger whole that is life on earth.”

Lessons from Milkweed

Just over a year later, in July of 2013, we visited once again to check in the seed production and record some of the process. On this visit, we learned several things. First, milkweed is an on-going production plant, it doesn’t set all of its flowers at once. There aren’t a crush of seed pods to be bagged, but there are little bunches of pods that always need bagging, so it is seemingly never done. Second, there is no real seed cleaning equipment available for the small scale grower to process and separate the seeds from the floss. There is large scale equipment that costs as much as a house, but nothing for the smaller grower. Third, there isn’t an established market for a regionally adapted milkweed seed of a specific species, as there hasn’t been any available up until now.

Since then, we have almost sold out of all of Painted Lady’s seed production, mostly to home gardeners but many garden centers and native plant nurseries are growing the seedling plugs or plants around the southwestern US. There is still Milkweed seed available! A number of school gardens, community gardens and Master Gardener groups have stepped forward to help re-establish the milkweed populations in their areas. We are honored to be part of such a project and amazed at the positive impact a decentralized, non-governmental, independent group of individuals that have mostly never met one another can have on such a large scale challenge.

More Varieties on the Way 

One of our dear friends, Gary Nabhan, gave a talk at Prescott College recently in collaboration with Make Way for Monarchs and we will be extending our collaboration with several growers of almost a dozen more southwest native species of milkweed that is being grown in southern Arizona this year. 

Stephen Scott is an heirloom seedsman, educator, speaker, soil-building advocate, locavore, amateur chef, artist and co-owner of Terroir Seeds with his wife, Cindy. They believe in a world of healthy soil, seed, food and people. Everyone has a fundamental need for vibrant food and health, which are interrelated. They welcome dialogue and can be reached at or 888-878-5247.Visit theirwebsiteand signup for theirNewsletterfor more education like this!