Gomphocarpus physocarpus
naturalizedApocynaceae

Gomphocarpus physocarpus

balloonplant

Naturalized (non-native)non-native

Introduced and now reproducing on its own in the wild.

Gomphocarpus physocarpus, commonly known as balloonplant, balloon cotton-bush, bishop's balls, nailhead, or swan plant, is a species of milkweed. The plant is native to southeast Africa, but it has been widely naturalized. It is often used as an ornamental plant. The name "balloonplant" is an allusion to the swelling bladder-like follicles which are full of seeds.

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Seasonality
21 flowering · 21 fruiting annotations · iNaturalist · fetched Jul 2026
JFMAMJJASONDpeak
flowering (peak August) fruiting (peak June)

This is an inference, not a schedule. The curve reflects when observers annotated flowering and fruiting — which tracks observer effort as well as plant behavior, and pools all elevations and islands into one signal. Hawaiʻi’s microclimates vary enormously; a species may fruit in January at sea level and June at elevation. Use this to know when to look, then look.

Gallery · 5 · iNaturalist
open-licensed photos · click any to view its source
Where documented · 101 ahupuaʻa
documented occurrences · iNaturalist + GBIF · iNaturalist 197 · GBIF 295 records
Kahakuloa · MauiiNat 86 · GBIF 76
Puʻuwaʻawaʻa · HawaiʻiiNat 9 · GBIF 17
Kahuku · HawaiʻiiNat 8 · GBIF 10
Keauhou · HawaiʻiiNat 4 · GBIF 11
Kaʻaʻawa · OʻahuiNat 5 · GBIF 7
Puʻuanahulu · HawaiʻiiNat 4 · GBIF 7
Makawao · MauiiNat 6 · GBIF 5
Kaʻūpūlehu · HawaiʻiiNat 2 · GBIF 8
Kapāpala · HawaiʻiiNat 3 · GBIF 4
Pūlehunui · MauiiNat 3 · GBIF 4
Kanaio · MauiiNat 1 · GBIF 5
Kamoku · LānaʻiiNat 2 · GBIF 4
Mākaha · OʻahuiNat 1 · GBIF 4
Hīleanui · HawaiʻiiNat 2 · GBIF 2
Kalaoa 1-5 · HawaiʻiiNat 2 · GBIF 2
Honuaʻula · HawaiʻiiNat 1 · GBIF 3
Momoualoa · HawaiʻiiNat 2 · GBIF 2
Kaunolū · LānaʻiiNat 1 · GBIF 3
Waiakoa · MauiiNat 2 · GBIF 2
Kawaipapa · MauiiNat 1 · GBIF 3
Waimea, Waikoloa · HawaiʻiiNat 2 · GBIF 2
Waiehu · MauiiNat 2 · GBIF 2
Waikapū · MauiiNat 2 · GBIF 2
Mokae · MauiiNat 1 · GBIF 3
Alaeakila, Kaapahu · HawaiʻiiNat 1 · GBIF 2
Kapulena · HawaiʻiiNat 1 · GBIF 2
Makaʻehu · MauiiNat 1 · GBIF 2
Wailuku · MauiiNat 1 · GBIF 2
Haʻikū · MauiiNat 1 · GBIF 2
Honuʻapo · HawaiʻiiNat 1 · GBIF 2
Hāliʻimaile · MauiiNat 1 · GBIF 2
Palauhulu 1-2 · HawaiʻiiNat 1 · GBIF 1
Palauea · MauiiNat 1 · GBIF 1
ʻŌmaʻopio · MauiiNat 1 · GBIF 1
Nienie · HawaiʻiiNat 1 · GBIF 1
Kalaupapa · MolokaʻiiNat 1 · GBIF 1
Kawela · HawaiʻiiNat 1 · GBIF 1
Kohanaiki · HawaiʻiiNat 1 · GBIF 1
Kēōkea · HawaiʻiiNat 1 · GBIF 1
Waiʻōhinu · HawaiʻiiNat 1 · GBIF 1
Koholālele · HawaiʻiiNat 1 · GBIF 1
Makapala, Niuliʻi · HawaiʻiiNat 1 · GBIF 1
Keāliakapu · LānaʻiiNat 1 · GBIF 1
ʻŌlaʻa · HawaiʻiiNat 1 · GBIF 1
Kapoaula · HawaiʻiiNat 1 · GBIF 1