North America Native Plant

Wiggins’ Swallow-wort

Botanical name: Cynanchum wigginsii

USDA symbol: CYWI4

Life cycle: perennial

Habit: vine

Native status: Native to the lower 48 states  

Synonyms: Basistelma angustifolia (Torr.) Bartlett, non CynanG.L. Chum angustifolium Pers. (BAAN4)  âš˜  Metastelma mexicanum auct. non (Brandeg) M. Fishbein & R. Levin (MEME13)   

Wiggins’ Swallow-wort: A Rare Arizona Native Worth Knowing About If you’re passionate about native plants and love discovering botanical treasures, you might be intrigued by Wiggins’ swallow-wort (Cynanchum wigginsii). This little-known perennial herb represents one of Arizona’s more elusive native species, and while you won’t find it at your local ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4: Status is uncertain but is somewhere between the following rankings: Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Wiggins’ Swallow-wort: A Rare Arizona Native Worth Knowing About

If you’re passionate about native plants and love discovering botanical treasures, you might be intrigued by Wiggins’ swallow-wort (Cynanchum wigginsii). This little-known perennial herb represents one of Arizona’s more elusive native species, and while you won’t find it at your local garden center, it’s worth understanding what makes this plant special.

What is Wiggins’ Swallow-wort?

Wiggins’ swallow-wort is a perennial forb—essentially a non-woody herbaceous plant that comes back year after year. As a member of the milkweed family (Apocynaceae), it shares DNA with more familiar plants like common milkweed, though this Arizona endemic has carved out its own unique niche in the Southwest.

The plant gets its name from botanist Ira Wiggins, and like many members of the milkweed family, it likely produces the characteristic milky sap that gives the family its common name.

Where Does It Grow?

This rare native is found exclusively in Arizona, making it a true southwestern specialty. Its limited distribution contributes to its conservation status and makes it a plant of particular interest to native plant enthusiasts and conservationists.

Conservation Status: Handle with Care

Here’s where things get important for responsible gardeners: Wiggins’ swallow-wort has a Global Conservation Status of S3S4, which indicates it’s somewhat rare to uncommon in its native range. This means if you’re interested in growing this plant, you need to be extra careful about sourcing.

If you want to grow Wiggins’ swallow-wort:

  • Only obtain plants or seeds from reputable native plant nurseries
  • Never collect from wild populations
  • Ensure any source can verify responsible propagation methods
  • Consider supporting conservation efforts for this species instead

Growing Wiggins’ Swallow-wort: The Challenge

Here’s the honest truth: detailed cultivation information for Cynanchum wigginsii is extremely limited. This isn’t unusual for rare native plants that haven’t entered mainstream horticulture. What we do know is that as an Arizona native perennial, it’s likely adapted to:

  • Arid to semi-arid conditions
  • Well-draining soils
  • Hot summers and mild winters typical of its native range
  • Minimal water once established

Should You Grow It?

The rarity of this plant presents both an opportunity and a responsibility. While growing rare natives can contribute to conservation efforts, it’s crucial to do so ethically. For most gardeners, especially those outside Arizona, focusing on other native milkweed family members might be more practical and equally beneficial for local ecosystems.

If you’re in Arizona and passionate about growing the rarest of the rare, Wiggins’ swallow-wort could be a worthy addition to a specialized native plant collection—but only with responsibly sourced material and a commitment to proper care.

Alternatives to Consider

If you’re drawn to the milkweed family but want more readily available options, consider these native alternatives:

  • Desert milkweed (Asclepias subulata) for Arizona gardens
  • Antelope horns (Asclepias asperula) for broader southwestern regions
  • Butterfly weed (Asclepias tuberosa) for eastern and central regions

The Bottom Line

Wiggins’ swallow-wort represents the fascinating diversity of our native flora, reminding us that there are still botanical mysteries hiding in plain sight. While it may not be the easiest plant to grow or find, knowing about species like this helps us appreciate the complexity and beauty of native plant communities.

Whether you choose to seek out this rare gem or simply appreciate it from afar, Wiggins’ swallow-wort serves as a perfect example of why protecting native habitats and supporting ethical native plant propagation matters. Sometimes the most special plants are the ones that remain a little wild and wonderful.

Wiggins’ Swallow-wort

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Gentianales

Family

Asclepiadaceae Borkh. - Milkweed family

Genus

Cynanchum L. - swallow-wort

Species

Cynanchum wigginsii Shinners - Wiggins' swallow-wort

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA