Gardening to help save the monarch butterfly

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According to the 24th annual Western Monarch Thanksgiving Count by the Xerces Society, there has been a “99.9% fall from the number of monarch in the 1980s, when butterflies filled trees from Marin County to San Diego County.” Over 1.2 million monarchs were counted in 1997. Despite an increase in volunteer monitors, the count of overwintering monarchs in forest groves along the coast of California during their migration in 2020 was a mere 2,000. Indeed, the numbers have shown a precipitous decline since monitoring began. As such, Xerces Society has issued a Call to Action.

Xerces Society Western Monarch Count
Notice that the blue line indicates an increase in sites
monitored from 1997 to 2020
Western Monarch Thanksgiving Count, Xerces Society

Friends of South Pasadena Nature Park Answers the Call

In 2016 Friends of South Pasadena Nature Park installed a Monarch Waystation in the park. We are now increasing our efforts to establish stands of narrowleaf milkweed on which the monarch butterflies lay their eggs. The eggs hatch out to caterpillars (larva) that only feed on milkweeds. Scientists believe that the loss of milkweed and nectar plants due to herbicide use, especially glyphosate (RoundupTM ), may be one of the reasons that monarchs are in trouble. We are working to establish local native plants that will provide both milkweed for caterpillars and nectar for the butterflies and other pollinators.

Grow Only Native Milkweeds

monarch with OE

In the park we only grow milkweed that is native to southern California. Scientific research (Satterfield, et al., 2016) suggests that the nonnative tropical milkweed may be linked to an increase in disease among monarchs. Since the nonnative tropical milkweed (Asclepias curassavica) does not go dormant, butterflies hang around for an easy life. Unfortunately, they also share diseases, such as the protozoan parasite,  Ophryocystis elektroscirrha or OE. It appears that OE is less prevalent in migratory monarchs because those infected with OE are unable to survive the journey and therefore are less likely to infect the larger population.

(Photo: Dara Satterfield / Project Monarch Health,

Get Your Own Free Native Milkweed Seed Packet

In addition to improving habitat at the nature park for the monarch (and other pollinators), Friends of the South Pasadena Nature Park is also reaching out to the public with information and native milkweed seeds. Beginning February 18th, volunteers will be at the South Pasadena Farmer’s Market with free seeds and information. Look for our Monarch Butterfly Waystation sign. The sign, also displayed in the nature park was created in 2019 by Carrie Hashimoto, at the time a high school student at Polytechnic School.

Monarch Waystation Poster
Interpretive sign from South Pasadena Nature Park will be on display at the Farmer’s Market

The following brochure with information and resources will be available along with the seed packets and planting information.

Monarch Brochure, p1
Monarch Brochure, pg 2

5 thoughts on “Gardening to help save the monarch butterfly

  1. Barbara, very gratified to see all that you and South Pasadena are doing. At Caltrans, where I work as a biologist, we’ve entered into a program with USFWS to set aside a percentage of right-of-way for milkweed and nectar-rich plants. Hopefully, it is not too late.


    • weedingwildsuburbia

      Thanks Paul. Glad to hear that USFWS and Caltrans are working on this critical problem as well. Time is short but I really hope we can turn this around!

  2. Thank you for posting this! I grew up near one of the traditional monarch parks… would love to plant some proper milkweed. Do you know if the same kind of milkweed is native further north? (A bit south of San Francisco.)

    • weedingwildsuburbia

      Hi Heather. I’d suggest that you contact your local chapter of CNPS. I checked and found that Asclepias fascicularis is very widespread and likely to be local to your area. Asclepias californica may be appropriate if you are in the East Bay. Xerces Society recommends that you don’t plant any milkweed if you are near overwintering sites (within 5 miles of the coast). Hope that helps.

    • weedingwildsuburbia

      Hi Heather. Do you know which Ceanothus it is? My experience is that Ray Hartman is one of the easiest ones to grow. About 10 years ago I planted 2 Conchas. The first summer after planting, one of them did what you describe. I watered it well and it promptly died. The following summer Concha number 2 did the same thing. This time I held off on watering, and it promptly died. I’m telling you this because sometimes watering or not does not help. It may be root rot or some other disease or stress.

      Having said this, I’d suggest checking the soil around the rootball carefully. If it is dry, water during the cool part of the day (early morning is best), and let the chips fall where they will. Also, while checking the soil for moisture, gently push your fingers into and around the rootball to check for gaps in the soil. If you find any, try to fill them in with you fingers. If it seems to respond positively to water, then let the area dry out and water deeply again – could be in 2 weeks depending on weather and soil type. Young plants like this usually need summer water (and winter water during dry seasons).

      Good luck and let me know how it goes.

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