North America Native Plant

Grisebach’s Swallow-wort

Botanical name: Cynanchum grisebachianum

USDA symbol: CYGR3

Life cycle: perennial

Habit: vine

Native status: Native to Puerto Rico âš˜ Native to the U.S. Virgin Islands  

Synonyms: Metastelma decaisneanum Schltr. (MEDE9)  âš˜  Metastelma grisebachianum Schltr. (MEGR13)   

Grisebach’s Swallow-Wort: A Caribbean Native Worth Knowing If you’re looking to add some Caribbean flair to your tropical garden, you might want to get acquainted with Grisebach’s swallow-wort (Cynanchum grisebachianum). This perennial herb is a true native of the Caribbean, calling both Puerto Rico and the U.S. Virgin Islands home. ...

Grisebach’s Swallow-Wort: A Caribbean Native Worth Knowing

If you’re looking to add some Caribbean flair to your tropical garden, you might want to get acquainted with Grisebach’s swallow-wort (Cynanchum grisebachianum). This perennial herb is a true native of the Caribbean, calling both Puerto Rico and the U.S. Virgin Islands home. While it might not be the showiest plant in your garden, this unassuming native deserves a spot on your radar if you’re passionate about supporting local ecosystems.

What Is Grisebach’s Swallow-Wort?

Grisebach’s swallow-wort is what botanists call a forb herb – basically, it’s a soft-stemmed perennial plant without woody tissue. Think of it as the opposite of a shrub or tree. This plant belongs to the milkweed family (Apocynaceae), which gives us a hint about its potential ecological value, even though specific details about this particular species are surprisingly scarce in gardening literature.

Where Does It Call Home?

This Caribbean native has a pretty exclusive address – you’ll find it naturally growing in Puerto Rico and the U.S. Virgin Islands. It’s perfectly adapted to life in these tropical island environments, which means it’s likely happiest in warm, humid conditions year-round.

Should You Grow It in Your Garden?

Here’s where things get a bit tricky. While Grisebach’s swallow-wort is definitely a legitimate native plant worth supporting, there’s frustratingly little information available about its specific growing requirements, appearance, or garden performance. This isn’t uncommon with some lesser-known native species – they simply haven’t been studied or cultivated as extensively as their showier cousins.

The Case for Growing Native Plants

Even without extensive horticultural information, there are compelling reasons to consider native plants like Grisebach’s swallow-wort:

  • They’re naturally adapted to local climate conditions
  • They support local wildlife and pollinators
  • They typically require less maintenance once established
  • They help preserve regional biodiversity

Growing Conditions (Best Guess)

Based on its native habitat in Puerto Rico and the U.S. Virgin Islands, Grisebach’s swallow-wort likely thrives in:

  • USDA hardiness zones 10-11 (tropical conditions)
  • Warm temperatures year-round
  • High humidity
  • Well-draining soils
  • Partial to full sun exposure

The Reality Check

Let’s be honest – finding this plant for your garden might be like searching for a needle in a haystack. It’s not commonly available in nurseries, and there’s limited cultivation information available. If you’re determined to grow Caribbean natives, you might have better luck with more well-documented species that share similar habitats.

Alternative Caribbean Natives to Consider

If you’re drawn to the idea of growing Caribbean native plants but want something with more available information and garden-proven performance, consider researching other native species from Puerto Rico and the Virgin Islands that are better documented and potentially more available in the nursery trade.

The Bottom Line

Grisebach’s swallow-wort represents one of those intriguing native plants that reminds us how much we still don’t know about our local flora. While it might not be the easiest plant to grow or find, it serves as a good reminder of the importance of supporting native plant research and conservation efforts. If you happen to encounter this species in the wild during your Caribbean travels, take a moment to appreciate this understated native – just remember to leave it where you found it!

For gardeners in tropical zones looking to support native ecosystems, the best approach might be to focus on well-documented Caribbean natives while keeping an eye out for more information about lesser-known species like Grisebach’s swallow-wort as botanical research continues to expand our understanding of these unique plants.

Grisebach’s 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 grisebachianum (Schltr.) Alain - Grisebach's 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