Late July and the Woolly-Pod Milkweed

Every year in late July, I hike along Vista Trail in O’Neill Regional Park to observe two healthy populations of wild milkweed growing along the trail. Last year at this time, the woolly-pod milkweed (Asclepias eriocarpa) plants were in full flower and bustling with bumblebee activity and hungry caterpillars.

Bumblebees (Bombus crotchii) gathering nectar from milkweed late July 2020. (E. Wallace)
Monarch caterpillars munching woolly-pod milkweed last July. (E. Wallace)

This year, I was surprised to see that the woolly-pod milkweed blossoms were dry and seed pods were already forming. And I didn’t see any monarch caterpillars on the plant.

Pods forming in late July 2021. (E. Wallace)

Did last winter’s drought (only 5 inches of rain) and this summer’s heat cause the woolly-pod milkweed plants to set seed early? And is this year’s change in the milkweed blossoms detrimental to the monarch butterfly population?

Seed pod development started early this year compared with last July. (E. Wallace)

A recent article in Popular Science magazine discussed findings from scientists who studied 25 years of data from more than 18,000 monarch counts to try to determine whether increased herbicide use, mortality during migration, or changes in climate might be most responsible for the decline in monarch numbers.

The magazine article summarized findings recently published in the July 19, 2021 scientific journal Nature Ecology & Evolution. The findings concluded that breeding season weather was nearly seven times more important than other factors in explaining the changes in summer monarch butterfly populations.

Michigan State University scientist Elise Zipkin and her team found that “monarchs tended to thrive when weather conditions stayed close to average in their spring breeding grounds, and when temperatures in the northern and southern parts of their summer habitat weren’t too cool or warm.”

The Nature Ecology & Evolution report concluded that “If observed changes in spring and summer climate continue, portions of the current breeding range may become inhospitable for monarchs. Results highlight the increasingly important contribution of a changing climate to insect decline.”

Although the study focused mainly on data from the eastern monarch population, it is likely the changing climate is also contributing to the precipitous decline of the western monarchs that inhabit our California landscapes.

Monarch visiting my garden. (E. Wallace)

I hope that we can learn from recent scientific studies to create change that will help support monarch butterfly populations. As I write this post on a hot summer afternoon, I see monarch butterflies in my yard. They are doing their best to cope with changing conditions. Let’s do what we can to help monarchs thrive.

Monarchs Arrive for Summer

Have you noticed monarch butterflies flying around your California yard this summer?

Western monarch butterflies are an iconic butterflies that delight us with bright orange plumage, black stripes, and white polka dots. They are so large, they cast a shadow when they fly overhead.

After hearing about the historically low overwintering monarch butterfly count last winter, I have been surprised to see a healthy number of western monarchs making daily visits to my home landscape over the past few months. 

Monarch rests on a native milkweed. (E. Wallace)

I am seeing more monarchs than I expected because last winter, fewer than 2,000 monarchs were counted overwintering in California. 

According to Xerces.org, “Early count numbers from Xerces’ Western Monarch Thanksgiving Count suggest that the western migratory population is headed for an all-time low. With approximately 95 percent of the data in, only 1,800 monarchs have been reported…This is a significant decline from the low numbers of the last two years where the total hovered just under 30,000 monarchs. These numbers are a tiny fraction of the millions of monarchs that likely visited overwintering sites in the 1980s and the hundreds of thousands of monarchs that graced California’s coast as recently as the mid-2010s. In fact, this represents an overall decline of more than 99.9% in the migratory population.”

Photo of overwintering Western monarch butterflies by Candace Fallon/Xerces Society

What can we do to help reverse their dramatic decline in numbers?

Monarch caterpillars only feed on milkweed. The first step you can take to help the western monarch butterfly is to plant milkweed that is native to your area. Good native milkweed choices for Southern California include narrow-leaf milkweed (Asclepias fascicularis) and woolly-pod milkweed (Asclepias eriocarpa). 

You can install native milkweed plants now, and support monarch butterflies looking for a host plant to lay their eggs. 

Western monarch caterpillars feasting on woolly-pod milkweed in Southern California. (E. Wallace)

Planting milkweed that is native to where you live is more beneficial than non-native (tropical milkweed) because non-native milkweed often hosts parasites that harm butterflies and disrupts their reproduction and migration.  

One nursery in Southern California is trying to help increase western monarch populations by offering a free trade-in. At Roger’s Gardens in Corona del Mar, you can bring your non-native tropical milkweed into the nursery and receive a free native narrow-leaf milkweed replacement plant.

Another great nursery to buy native milkweed is Tree of Life Nursery in San Juan Capistrano. Tree of Life Nursery has several species of native milkweed plants for sale this year including woolly-pod milkweed shown above.

Monarch caterpillar munching native narrow-leaf milkweed yesterday. (E. Wallace)

Planting plenty of native milkweed in your garden is a great first step in helping the western monarch butterfly populations recover. I will discuss more ways you can help monarchs in my next post. In the meantime, visit your local nursery and buy several milkweed plants for your garden, and while you are outside, look for monarchs cruising your garden.

Summer Buckwheat Blooms Bright

It is July, the height of summer in Southern California, and buckwheats are blooming with thousands of showy white flowers.

(E. Wallace)

I took a walk this morning at my favorite local park, O’Neill Regional Park in Trabuco Canyon. Many of the spring-blooming plants are hunkering down in the 90-degree heat, but California buckwheat (Eriogonum fasciculatum) is just beginning to shine. Look closely and you will see clouds of tiny butterflies and pollinators flying from blossom to blossom, gathering pollen.

Gray hairstreak butterfly. (E. Wallace)

Beetles too are enjoying the buckwheat blossoms.

(E. Wallace)

In the photo below, notice the tiny fly (upper left corner) coming in toward the buckwheat flower while the Flower Longhorn Beetle forages.

(E. Wallace)

If you are looking for a summer-blooming shrub for your garden, buckwheat should be one of your top choices. Buckwheats bloom for months during the hottest parts of the year and support clouds of pollinators, butterflies, and birds. Buckwheats are easy to grow, and once established, require no supplemental water.

(K. Ethington)

Try planting a buckwheat interspersed with salvias, fuchsias, and mallows. You will get year-round blossoms in your garden and year-round butterflies too. Add a native milkweed, such as narrow-leaf milkweed (Asclepias fascicularis), and support declining monarch butterfly populations.

(E. Wallace)

Native plants are gaining popularity as gardeners learn to appreciate their beauty and importance to wildlife. Join the movement! Try planting a buckwheat and see how many pollinators are attracted to your landscape. Then add more. Butterflies will flutter, birds will sing, and you will be filled with happiness.

(S. Bressler)

Where Do Western Monarchs Spend the Spring?

Despite the fact that Western Monarch butterflies are universally loved, their numbers have plummeted in recent years.

Two monarch butterflies cruise together under a Coast Live Oak tree. (Elizabeth Wallace)

What can you do to help? Join the Western Monarch Mystery Challenge–a campaign created to increase awareness of locations where Western Monarchs spend the spring in California after leaving their coastal California overwintering sites.

Male and female Western Monarchs together. Photo by Jeff Wallace.

If you see a monarch from February 18 through April 22, take a photo (it can be far away and blurry). Then report the siting to iNaturalist, the Western Monarch Milkweed Mapper, or email it to MonarchMystery@wsu.edu.

Far away and blurry photo of Western Monarch on baccharis pilularis cultivar and coffee berry. (Elizabeth Wallace)

Your photo will help scientists better understand Western Monarchs’ locations and activities in February, March, and April. When you share your springtime Monarch observations, you help conservation efforts for the butterfly.

In between reporting your spring Western Monarch sitings, plant more native plants in your garden, especially California buckwheat, salvias, manzanitas, narrow-leaf milkweed, and maybe a scrub oak tree!