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Monday, January 12, 2015

Encouraging Monarch Butterfly in the Mojave Desert?

Q. I've been thinking about growing milkweed plants to help in the Monarch fight. Two varieties look worth pursuing Asclepias EROSA and SUBULATA. Any thoughts?

A. I grew up in the Midwest and in the path of Monarch butterflies migration routes to Mexico. In fact, as a boy I volunteered to monitor Monarch butterflies for a research study done in Canada back in the 1960's.

After moving to southern Nevada I have not seen any Monarch butterflies in the 30 years I've been here in the Las Vegas Valley. My understanding is there are two migration routes; one from the eastern population of Monarch butterflies and one from the Western population.

Map of Monarch butterfly routes

The eastern population misses us completely in the Western population is pretty much restricted from us by the Sierra Nevada Mountains.

Encourage and sustain local populations. I agree with you wholeheartedly on encouraging our local populations of butterflies and moths. They had a lot of beauty and grace to our landscape and provide some pollination and a food supply. Instead of focusing just on milkweeds I think a diversity of plant material for attracting these insects might be important.

Be careful of pesticide use. Also, reducing or eliminating pesticide use in the butterfly garden area would be wise. There are a number of pesticides that are harmful including two that I recommend frequently to organic gardeners: Bt and Spinosad. When considering pollinators both of these insecticides can be lethal, in particular Spinosad to bees.

Always apply pesticides, if they must be applied, at times when these creatures are not active. This means the very early morning hours. Many of our moths fly at night so I would avoid applying pesticides at dusk if a major concern are night flying moths.

Further reading. I put together some links on general information on Monarch butterflies, moths and butterflies of southern Nevada and how to make a butterfly garden. I wish you much success.

Wikipedia on Monarch butterflies
Donate to Wikipedia

Threats to Monarch butterflies

Butterflies of southern Nevada.

How to make a butterfly garden in the southwestern desert of the US


  1. I have seen two monarch butterflies in the last two years. One was flying around my yard and I took pictures of it. I also had a monarch caterpillar last year.

    1. After looking at some of the information you posted about butterflies here in Nevada I think the butterflies I saw were actually Queen butterflies. Thanks for all the information.

  2. I didn't think monarchs came through southern Nevada either but I had two milkweed plants ( A. subulata ) that each had about 4 monarch caterpillars on them this fall in to early winter. I don't know if any survived to become butterflies but I guess they do on occasion come through the Las Vegas area.
    I even sent some pictures of them to www.facebook.com/SouthwestMonarchStudy where they posted a few of my caterpillar pictures.

  3. We do get Monarch butterflies here in Las Vegas and they reproduce around their migration time which peaks at the end of September in our area. I have taken photos of Monarch (and Queen) caterpillars and chrysalis on Asclepias subulata. Monarch caterpillars have also been observed locally on Asclepias curassavica (Tropical Milkweed). The University of Nevada Cooperative Extension Master Gardeners are experimenting with a wide range of Milkweeds including 5 natives to see which ones are suitable for local residential gardens. You can get free seeds of Asclepias subulata with instructions on how to germinate them from the Master Gardener office :)