Desert Milkweed
ExplorePlants
Desert Milkweed
asclepias erosa
Desert Milkweed (Asclepias erosa) is a robust, erect perennial herb native to the arid desert regions of the southwestern United States and northwestern Mexico. It stands out in barren landscapes with its thick, fibrous stems and large, coarse, pale green leaves. During the intense heat of late spring and summer, it produces dense, globe-like clusters of pale yellow to greenish-white flowers that act as critical nectar oases for desert pollinators. Like other milkweeds, it produces a sticky, milky latex sap filled with toxic cardenolides, which serves as a powerful defense mechanism against generalist herbivores while hosting highly specialized insect species.
Habitat: Found in sandy, gravelly washes, desert flats, disturbed roadsides, and dry slopes below 1,500 meters in arid desert regions.
Appearance
This sturdy perennial grows up to 60 to 200 centimeters tall, featuring stout, erect stems typically covered in fine, velvety white hairs. Its large, opposite leaves are sessile, broadly oval-to-lanceolate, and have a distinctive pale grayish-green hue with prominent white veins. The plant is easily recognized by its spectacular spherical flower clusters (umbels) that measure 5 to 10 centimeters across, containing numerous small, 5-petaled flowers ranging in color from cream to pale yellow-green. Following pollination, it produces large, teardrop-shaped seed pods that split open to release flat, brown seeds attached to silky white tufts.
KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderGentianalesFamilyApocynaceaeGenusAsclepias
Category
PlantsRarity
Common
Danger
1/5 · Very low
Snaps
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Interesting facts
Indigenous peoples of the Southwest historically harvested the fibers from the plant's tough, woody stems to spin extremely strong cordage for bowstrings and nets.
The toxic cardiac glycosides concentrated in this plant are sequestered by monarch caterpillars, making both the caterpillar and the adult butterfly poisonous to birds.
Unlike typical flowers that disperse loose pollen grains, Desert Milkweed packages its pollen in specialized, sticky structures called pollinia that clip onto the legs of visiting insects.
Special abilities
Ability
Chemical Defense Shield
Produces a thick, sticky white latex sap rich in cardiac glycosides (cardenolides) that are highly toxic to most generalist herbivores.
Ability
Drought-Resistant Fuzz
Stems and leaves are covered in fine, velvety trichomes (hairs) that reflect intense desert sunlight and reduce moisture loss from wind.
Ability
Wind-Assisted Dispersal
Develops lightweight seeds equipped with silky, floss-like hairs that easily catch desert drafts to colonize distant areas.
Measurements & details
- Length
- 60-200 cm
- Lifespan
- 3-15 years
Diet & Feeding
As a photosynthetic plant, it generates its own energy from sunlight, water, and carbon dioxide, while drawing minerals from the desert soil.
Primary Foods
- Sunlight
- Carbon dioxide
- Water
- Soil nutrients
Foraging Method
- Photosynthesis
Ecological connections
host plant
Monarch Butterfly
Danaus plexippus
Acts as a primary larval host plant where caterpillars feed on leaves, absorbing cardenolides to become toxic to predators.
host plant
Queen Butterfly
Danaus gilippus
Provides essential foliage for caterpillars and nectar for adult butterflies in extreme desert environments.
mutualism
Tarantula Hawk Wasp
Pepsis grossa
Adult wasps feed heavily on the abundant, high-energy nectar produced by the flowers, aiding in pollination.
Traits
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Also known as
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Safety
Danger
1/5 · Very low
No special safety notes yet.
Frequently Asked Questions
How to identify Desert Milkweed?
The easiest way to identify Desert Milkweed is to use the Snappit nature identifier app.
How long is Desert Milkweed?
60-200 cm
How long does Desert Milkweed live?
3-15 years
What does Desert Milkweed eat?
As a photosynthetic plant, it generates its own energy from sunlight, water, and carbon dioxide, while drawing minerals from the desert soil.
Where is Desert Milkweed usually found?
Found in sandy, gravelly washes, desert flats, disturbed roadsides, and dry slopes below 1,500 meters in arid desert regions.
How does Desert Milkweed hunt?
Photosynthesis
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