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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 Arizona. We hope to expand the list to the entire southwest. They are labeled whether they are more likely to grow in the low or high desert areas of the state.

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?

We now have a short video about starting low desert milkweeds from seeds. Look for information about the higher elevation milkweeds soon.

Tropical Milkweed (Asclepias curassavica) In The News


Table of contents

Arizona Milkweed (Asclepias angustifolia)
Antelope Horn or Spider Milkweed (Asclepsias asperula)
Tropical Milkweed Blood Flower (Asclepias curassavica)
Engelmann’s Milkweed (Asclepias engelmanniana)
Desert Milkweed (Asclepias erosa)
Broadleaf or Popcorn Milkweed (Asclepsias latifolia)
Pine-needle Milkweed (Asclepias linaria)
Mojave Milkweed (Asclepias nyctaginifolia)
Zizotes Milkweed (Asclepias oenotheroides)
Showy Milkweed (Asclepsias speciosa)
Rush or Desert Milkweed (Asclepsias subulata)
Horsetail Milkweed (Asclepias subverticillata)
Butterfly Weed (Asclepias tuberosa)


Butterfly Weed
(Asclepias tuberosa)

High Desert
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Pine-needle Milkweed
(Asclepias linaria)

Low Desert
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Desert Milkweed
(Asclepias erosa)

Low Desert
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Mojave Milkweed
(Asclepias nyctaginifolia)

High and Low Desert
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Horsetail Milkweed
(Asclepias subverticillata)

High and Low Desert
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Arizona Milkweed
(Asclepias angustifolia)

Low Desert
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Engelmann’s Milkweed
(Asclepias engelmanniana)

High Desert
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Zizotes Milkweed
(Asclepias oenotheroides)

High and Low Desert
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Rush or Desert Milkweed
(Asclepsias subulata)

Low Desert
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Antelope Horn or Spider Milkweed
(Asclepsias asperula)

...
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Broadleaf or Popcorn Milkweed
(Asclepsias latifolia)

...
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Showy Milkweed
(Asclepsias speciosa)

...

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