Importance of Milkweed

Milkweed is crucial to the life-cycle of the monarch butterfly. Female monarchs search for milkweed to lay their eggs. Monarch larvae (caterpillars) will only feed on milkweeds in the Asclepias family. There are 108 species of milkweed in North America. Monarchs are only known to use 30 of them, but they may use any or all of them. Below is a list of milkweeds that Monarchs favor in the southwest. They are labeled where they are most likely to grow. Most species of milkweed contain cardiac glycosides. When the caterpillars consume the leaves, they become toxic to many predators. This protection continues when they become butterflies. Predators learn to avoid monarch larvae and butterflies because they taste bad or make them vomit. There is a wide variation in toxin strength in different kinds of milkweed.

Desert Milkweed (Asclepias subulata)

Want to grow your own milkweed from seeds? Click here

Best practices for growing and watering new milkweed seedlings Click here

Cold stratification not always needed for milkweed seeds in the southwest Click here

Pollinator Plants of the Desert Southwest-Native Milkweeds Click here

Tropical Milkweed (Asclepias curassavica) In The News

Butterfly Weed (Asclepias tuberosa) AZ mid & low elevations, CO, NM, southern UT
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Pine-needle Milkweed (Asclepias linaria) AZ low desert
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Desert Milkweed (Asclepias erosa) AZ CA NV low deserts
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Narrowleaf Milkweed (Asclepias fascicularis) Northern NV
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Mojave Milkweed (Asclepias nyctaginifolia) AZ high and low deserts
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Horsetail Milkweed (Asclepias subverticillata) AZ CO NM southern UT
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Arizona Milkweed (Asclepias angustifolia) AZ low Desert
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Engelmann’s Milkweed (Asclepias engelmanniana) AZ high deserts
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Zizotes Milkweed (Asclepias oenotheroides) AZ high and low deserts
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Rush or Desert Milkweed (Asclepsias subulata) AZ CA NV low deserts
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Antelope Horns or Spider Milkweed (Asclepsias asperula) AZ CO NM southern NV & UT
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Broadleaf or Popcorn Milkweed (Asclepsias latifolia) AZ NM southern UT
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Showy Milkweed (Asclepsias speciosa) AZ CO northern NV & UT

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