# Balloon Plant (Gomphocarpus physocarpus)

> Not a true milkweed but a close African relative, grown everywhere for its extraordinary inflated, bristly, balloon-like pods. Monarchs will use it as a host, and in frost-free regions it raises exactly the same winter-breeding concerns as tropical milkweed.

Source: https://milkweedusa.com/species/balloon-plant/  
Licence: CC BY 4.0 (Milkweed USA)

## Summary

Not a true milkweed but a close African relative, grown everywhere for its extraordinary inflated, bristly, balloon-like pods. Monarchs will use it as a host, and in frost-free regions it raises exactly the same winter-breeding concerns as tropical milkweed.

## Key facts

| Field | Value |
| --- | --- |
| Scientific name | Gomphocarpus physocarpus E. Mey. |
| Genus | Gomphocarpus |
| Family | Apocynaceae |
| Common names | Balloon Plant, Hairy Balls, Swan Plant, Balloon Cotton Bush |
| Status | Not native to the United States |
| Height | 3 ft–6 ft |
| Spread | 2 ft–4 ft |
| Flower color | white, cream |
| Bloom period | May to October |
| Light | Full sun |
| Soil moisture | Average |
| USDA zones | 8-11 |
| Leaf arrangement | opposite |
| Leaf shape | narrow |
| Sap | Milky latex |
| Root system | Fibrous, clump-forming and easy to move |
| Seed stratification | None required |
| Monarch value (0-5) | 3 |
| Garden value (0-5) | 3 |
| Nectar value (0-5) | 3 |
| US states recorded | Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina, Texas |

## Identification

- Pods are pale green spheres covered in soft bristles, unmistakable and unlike any Asclepias.
- Small waxy white flowers hanging in nodding clusters.
- Tall, shrubby, softly hairy stems with narrow willow-like leaves.

## Ecology

Monarch larvae develop successfully on it, and it is widely used in butterfly houses and school rearing projects. It is native to southern Africa, not North America.

## Growing

Easy from seed with no stratification and fast enough to flower in one season, so it is best grown as an annual in cold regions. In zones 9 and warmer, cut it back through winter or use a native species instead.

## Cautions

Non-native. In frost-free regions its evergreen growth encourages winter monarch breeding and OE parasite build-up, exactly as tropical milkweed does.

## Questions

**Is balloon plant the same as milkweed?**

It is a close relative in the same subfamily, not a true Asclepias. Monarch caterpillars do eat it, but it is native to southern Africa. In frost-free regions the same winter-breeding cautions apply as for tropical milkweed.

## References

- Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:97670-1
- GBIF: https://www.gbif.org/species/3170326
- iNaturalist: https://www.inaturalist.org/taxa/281273
- Wikipedia: https://en.wikipedia.org/wiki/Gomphocarpus_physocarpus
- NatureServe: https://explorer.natureserve.org/Search?searchTerm=Gomphocarpus%20physocarpus

## Photographs

- Gomphocarpus physocarpus flower buds1 (14439930407) (Harry Rose from South West Rocks, Australia, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Gomphocarpus_physocarpus_flower_buds1_(14439930407).jpg
- Gomphocarpus physocarpus flower4 (14626324605) (Harry Rose from South West Rocks, Australia, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Gomphocarpus_physocarpus_flower4_(14626324605).jpg
- Gomphocarpus physocarpus habit4 (14603314966) (Harry Rose from South West Rocks, Australia, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Gomphocarpus_physocarpus_habit4_(14603314966).jpg
- Balloon Plant photographed in Blyde River Near Hoedspruit: Blyde river alongside floodplain. (Wynand Uys, CC BY 4.0): https://www.inaturalist.org/observations/10847450
- Balloon Plant photographed in WHVF+F66, San Luis de Cañete 15720, Perú (Public domain (CC0), CC0): https://www.inaturalist.org/observations/199189628
- Balloon Plant photographed in Cacadu, ZA-EC, ZA (Henry de Lange, CC BY 4.0): https://www.inaturalist.org/observations/12454057
- Balloon Plant photographed in Glenroy Place, Port Elizabeth, EC, ZA (Andrew Gillespie, CC BY-SA 4.0): https://www.inaturalist.org/observations/104447206
- Balloon Plant photographed in Stellenbosch, WC, ZA (Dave Richardson, CC BY 4.0): https://www.inaturalist.org/observations/73022814

## How to cite

Milkweed USA. (2026). Balloon Plant (Gomphocarpus physocarpus). https://milkweedusa.com/species/balloon-plant/