Gomphocarpus physocarpus

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Here's what it looks like (click to embiggen for necessary detail):

Photograph by Yixue Yang, who gave it the name "spiked lantern".

Quiz:  before going to the next page, please give it whatever name you think is most appropriate, based on its shape or whatever other attributes you can glean from the photograph.

This is a plant with many names, so don't feel shy about giving it one of your own.  We'll talk about that more below.

As for the Linnaean designation, the genus name comes from the Greek words gomphos meaning "bolt" or "nail" and karpos meaning "fruit".  The specific epithet from Greek means "bladder" (physo) and "fruit" (karpos).  Source.

Gomphocarpus physocarpus, commonly known as hairy ballsballoonplantballoon cotton-bushbishop's ballsnailhead, 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 "hairy balls" is an allusion to the swelling testicle-like follicles which are full of seeds.


A few other names:

… balloon milkweed, … elephant balls, … monkey balls, … and many others.


The horticulturalist who grew this plant and sold it to me said that a friend of hers — in what is apparently an in-joke — affectionately called it "Harry balls", though I couldn't tell the difference from "hairy balls" when spoken.

So what did you call it?


  1. Philip Taylor said,

    October 13, 2019 @ 1:38 pm

    Initially, "gooseberry gourds", but when I realised that the "gourds" must be quite light as the stems appear to be easily supporting their weight, I amended it to "gooseberry gourd-lanterns".

  2. DMBG said,

    October 13, 2019 @ 2:03 pm

    The small image made me think "giant gooseberry", but a closer look does suggest paper lanterns rather. I'll split the difference and settle for "brantern".

  3. Diana S. said,

    October 13, 2019 @ 2:24 pm

    I've heard of the name "pufferfish fruit," for they look like angry little pufferfish.

  4. Victor Mair said,

    October 13, 2019 @ 2:35 pm

    Another scientific name for the plant is Asclepias physocarpa, where the genus was so styled by Linnaeus after Asclepius, the Greek god of healing.

  5. Ellen K. said,

    October 13, 2019 @ 2:38 pm

    My first thought was they remind me of watermelons, but smaller, but that didn't for me lend itself to an imagined name. On 2nd view, paper lantern plant.

  6. Keith said,

    October 13, 2019 @ 2:39 pm

    I would have called it "lantern cane"… But "Bishop's balls" is just too funny.

    It reminds me of a conversation I once had with the Italian owner of an cheese shop; I bought a cheese from him that he called "borsa di Papa", and he explained to me that it meant "the Pope's scrotum"…

  7. Victor Mair said,

    October 13, 2019 @ 3:01 pm

    The Japanese name is "fūsentōwata フウセントウワタ / 風船唐綿" ("balloon milkweed").

  8. Victor Mair said,

    October 13, 2019 @ 3:34 pm

    The German is "Schwanen-Seidenpflanze" ("swan silk plant") and the French is "arbre à ballons" (balloon tree").

  9. jn defang said,

    October 13, 2019 @ 3:47 pm

    Name, shmame. Whether you call it swan silkweed or one of the more risqué names, it's still hideous. ornamental plant? Not in my garden.

  10. Viseguy said,

    October 13, 2019 @ 4:57 pm

    I also was reminded of melons. How about "miter melons", a more polite play on "bishop's balls"? I have to agree with jn defang, though, on the aesthetics of this plant. And its various common names don't help, either. "Spiked lantern" is the most promising rehabilitator, especially if you're into spikes.

  11. Thomas Rees said,

    October 13, 2019 @ 5:22 pm

    Monarch butterfly advocates discourage the planting of exotic milkweeds.

  12. Ray said,

    October 13, 2019 @ 7:10 pm

    I spotted this plant at a phs (pennsylvania horticultural society) "pop-up" garden a couple of years ago and asked the bespectacled white-hairbunned lady in charge what they were and she said, without blinking an eye, "Bishop's Balls."

    and so they are. Bishop's Balls.

  13. Victor Mair said,

    October 13, 2019 @ 7:24 pm

    @Thomas Rees

    Please explain why.

  14. Victor Mair said,

    October 13, 2019 @ 8:44 pm

    Harry Baals


    Harry William Baals (November 16, 1886 – May 9, 1954) was the Republican Mayor of Fort Wayne, Indiana, from 1932–1947 and from 1951 until his death in 1954. He had two children: Marceil D. Baals Smith and Donald Baals.

    Fort Wayne newscaster Bob Chase, of WOWO-AM, relates a story that he once pronounced the mayor's name "Bales." Mayor Baals personally called him following the broadcast to correct his pronunciation, saying, "son, this is your Mayor. I pronounce my name 'Balls'."

    Hairy ball theorem


    The hairy ball theorem of algebraic topology (sometimes called the hedgehog theorem in Europe) states that there is no nonvanishing continuous tangent vector field on even-dimensional n-spheres. For the ordinary sphere, or 2‑sphere, if f is a continuous function that assigns a vector in R3 to every point p on a sphere such that f(p) is always tangent to the sphere at p, then there is at least one p such that f(p) = 0. The theorem was first stated by Henri Poincaré in the late 19th century,[citation needed] and first proven in 1912 by Luitzen Egbertus Jan Brouwer.

    The theorem has been expressed colloquially as "you can't comb a hairy ball flat without creating a cowlick" or "you can't comb the hair on a coconut".

  15. njun said,

    October 13, 2019 @ 9:45 pm


  16. Victor Mair said,

    October 13, 2019 @ 10:34 pm

    From Tong Wang:

    "Green globefish" or "puffed puffer". They look so much like puffed globefish.

  17. Jerry Friedman said,

    October 13, 2019 @ 11:07 pm

    Prof. Mair: The Xerces Society's Milkweed FAQ discourages the planting of one exotic species, Asclepias curassavica in the southern U.S. because it blooms all year there and thus encourages monarchs to stay all winter, which increases their incidence of infection by a parasite. The society recommends planting only locally native milkweeds.

    This page from Envirobites gives another reason: in very hot weather A. curassavica produces cardenolides (the toxins that monarchs assimilate to protect themselves from predators) at such high levels that they seem to harm the monarchs.

    By the way, in looking for that I found yet another orchidaceous name, "family jewels milkweed". I think people have strange imaginations.

  18. Victor Mair said,

    October 13, 2019 @ 11:09 pm

    From Frank Chance:

    Also written as 風船唐綿, a combination of two two-character words.
    風船 is a common Japanese (and Chinese??) word for a balloon, “wind ship". The green globes (fruit) on the plant look a lot like 紙風船 kami fûsen Japanese paper balloons, hence the name.

    唐綿 is in two parts as well, tô (Tang, i.e. Chinese) and wata, cotton.

  19. Vireya said,

    October 14, 2019 @ 12:12 am

    I've known it as swan plant since I was a child. It isn't obvious from that photo, but if you break the pods off leaving the curved stem attached, you can float them in water and they look just like little green swans swimming around. Now my childhood innocence has been shattered by all these testicular allusions!

  20. Cheryl Thornett said,

    October 14, 2019 @ 12:19 am

    My first glance at an incomplete image suggested 'tennis ball plant', since they looked round rather than the oval a more complete image shows.

  21. champacs said,

    October 14, 2019 @ 12:31 am

    Here in Reunion (French and Creole speaking island in Indian Ocean) the plant is called "Couilles du pape" (Pope's balls) (cf. Keith and the Italian cheese he mentions).

  22. R. Fenwick said,

    October 14, 2019 @ 1:30 am

    before going to the next page, please give it whatever name you think is most appropriate

    Too late. I've known it as wild cotton since I was a small child and saw it growing feral on my Grandpop's farm (in Caloundra, Queensland, Australia).

  23. Hans Adler said,

    October 14, 2019 @ 4:15 am

    I called it "balloon plant". Which turned out to be not original at all.

  24. Theodore said,

    October 14, 2019 @ 1:18 pm

    I couldn't participate in the quiz because these are readily available at the downtown Chicago farmers markets, where at least one vendor (Oosterhoff & Son) calls them "hairy balls".

  25. Yerushalmi said,

    October 14, 2019 @ 2:32 pm

    The holiday of Sukkot started today, so when I saw this post I thought it was headed in an entirely different direction.

  26. Nicki said,

    October 22, 2019 @ 1:02 am

    Green moon

    I may have been influenced by a menu item I saw recently, called Lotus Pond Moonlight! 荷塘月色

    From the photo, it appeared to be a lotus root stir fry, with sliced carrots, snow peas, wood ear, etc. It's a dish that I enjoy, but I've never seen it called that before.

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