Flower profile
Horsetail milkweed
Asclepias subverticillata
Horsetail milkweed is a wildflower that USDA PLANTS lists as native in the lower 48 states. In New Mexico it's most often seen in bloom in June–September.
*iNaturalist research-grade observations, as of October 17, 2026.
On our lists for: New Mexico
Quick look
Asclepias subverticillata is a plant found in the southwestern United States and Mexico. Common names include horsetail milkweed, poison milkweed and whorled milkweed.
- It belongs to the Apocynaceae family. iNaturalist
- USDA PLANTS describes it as an herb (forb) with a perennial life cycle. USDA PLANTS
- USDA PLANTS lists it as native in the lower 48 states and records it in 12 states. USDA PLANTS
- NatureServe lists it as native to New Mexico. NatureServe
- In New Mexico, most iNaturalist sightings of it in flower come in June–September. iNaturalist
- iNaturalist has 1,508 research-grade sightings of it in New Mexico, ranking #23 among the 109 flowers on our New Mexico list. iNaturalist
Horsetail milkweed gift ideas
Handmade horsetail milkweed gifts from independent makers.
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Horsetail milkweed art print
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Horsetail milkweed greeting card
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Horsetail milkweed mug
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Horsetail milkweed earrings
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Horsetail milkweed embroidery pattern
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Horsetail milkweed sticker
When does it bloom?
In New Mexico, most flowering sightings come in June–September.
Conservation status
- Federal (U.S. ESA)
- Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
- NatureServe global
- G4 Apparently secure worldwide. NatureServe
- New Mexico
- Not listed Not on New Mexico state endangered plant species (19.21.2.9 NMAC). NatureServe: SNR, not yet ranked in New Mexico. 19.21.2.9 NMAC
- Rare elsewhere
- Other states where NatureServe ranks it rare or missing: WY (SH). (S1 critically imperiled, S2 imperiled, SH possibly extirpated, SX presumed extirpated.)
Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.
Can you eat it?
None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.
ASPCA's entry “Milkweed” (Asclepias species), which covers the whole genus, lists it as toxic to dogs, cats and horses. Signs include: Vomiting, profound depression, weakness, anorexia, and diarrhea are common; may be followed by seizures, difficulty breathing, rapid, weak pulse, dilated pupils, kidney or liver failure, coma… ASPCA
🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.
Where does it grow?
USDA PLANTS records horsetail milkweed in 12 states.
recorded by USDA PLANTS on our state lists not recorded
See the full list of states
Arizona, Colorado, Idaho, Kansas, Missouri, Nebraska, Nevada, New Mexico, Oklahoma, Texas, Utah, Wyoming.
New Mexico counties with USDA records: Bernalillo, Catron, Chaves, Colfax, Curry, De Baca, Dona Ana, Eddy, Grant, Hidalgo, Lea, Lincoln, Los Alamos, McKinley, Mora, Quay, Rio Arriba, Roosevelt, San Juan, San Miguel, Sandoval, Santa Fe, Socorro, Taos, Torrance.
More New Mexico flowers
Sources
- USDA, NRCS. PLANTS Database, profile ASSU2.
- iNaturalist, Asclepias subverticillata: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
- Wikipedia, Asclepias subverticillata (lead quoted under CC BY-SA 4.0).
- New Mexico: New Mexico state endangered plant species (19.21.2.9 NMAC).
- New Mexico: New Mexico Noxious Weed List (NM Department of Agriculture, updated June 2020).
- USFWS, ECOS species database (ESA listing check), October 17, 2026.
- NatureServe Explorer, Asclepias subverticillata (global and state ranks).
- Edibility and toxicity: ASPCA.
- Photo: Michelle W. （鍾偉瑋） via iNaturalist · CC BY 4.0 · resized.