Botanical mystery of hairy, green ‘balloons’ is solved
I stopped by a roadside stand in Kimberton about two weeks ago to buy some flowers. I was so wowed by the big, beautiful dahlias in the mixed-fall-flowers bouquet that I didn’t even notice the large, hairy, pale green, balloon-y things tucked into the middle. Running from one thing to the next on a busy morning, I just plunked the whole rubberbanded batch into water when I got home and didn’t notice the spherical oddities until I refilled the vase a few days later. It was a big bouquet, but still . . . I honestly don’t know how I missed something so large — each about three inches in diameter — and so strange.
What was this plant that produced such bizarre structures? I typed “plant with large pale green hairy seed pods” into a search field and got a positive I.D. What had arrived in the bouquet were seed pods of balloon plant (Gomphocarpus physocarpus), a member of the Milkweed Family native to southern Africa. A tender perennial in Zones 8 to 10, it can be grown as an annual in colder zones. It can reach a height of 8 to 10 feet, with a spread of from 2 to 3 feet. It likes full sun, tolerates deer and drought, and requires little maintenance. However, in warmer climates, balloon plant can become invasive.
Smallish, white flowers appear in July and August, but are not particularly prominent; it’s the seed pods that steal the show. Unsurprisingly — check out the photo — another common name for this plant is “hairy balls.” The pods can be used in flower arrangements either fresh or dried.
Expecting to find seeds that looked like other milkweed seeds, I cut open one of the pods. However, if anything, what was already strange looking became even stranger. The pod was mostly empty, with a crescentshaped, interior pod. Connecting that inner pod to the inside surface of the outer pod were dozens of delicate, white filaments. I cut into the inner pod and there, finally, were the milkweed-like seeds. But this gave me something else to puzzle over: Why the outer, balloon-like layer? Why filaments?
On the websites that popped up from my search, I learned that the botanical name of the balloon plant was formerly Asclepias physocarpa. “Asclepias” is the genus name for milkweeds. The inner pod and the seeds were certainly reminiscent of the other milkweed plants I’ve seen. And I learned that there’s an additional connection: The balloon plant attracts monarch butterflies
At monarchbutterflygarden. net, I learned that there are many more common names for Gomphocarpus physocarpus: Goose plant, Giant swan plant,
Family jewels, Oscar, and Cotton-bush. The site also listed a number of milkweed growing tips:
From Seed:
Start seeds indoors, two months before last frost. In our area, that would be in early March. Direct seeding is not recommended below USDA Zone 8. (We are mostly in Zone 7, so not recommended here.) Soak seeds in water for 24 hours before planting. Seeds may apparently also be started in water.
Propagating from Existing Plants:
Take cuttings, and place stems in water until roots appear. Rooting hormone may help.
Purchase Plants:
Always a good option. Plus, if you’re interested in collecting seeds from your plants, in annual zones (e.g., our Zone 7), starting with plants is the best option to insure that plants have time to set seed.
I also found a short video on how to easily separate milkweeds seeds from their fluff: https://monarchbutterflygarden. net/harvest-milkweed-seeds-nofluff/
Pam Baxter is an avid organic vegetable gardener who lives in Kimberton. Direct e-mail to pamelacbaxter@gmail.com, or send mail to P.O. Box 80, Kimberton, PA 19442. Share your gardening stories on Facebook at “Chester County Roots.” Pam’s book for children and families, Big Life Lessons from Nature’s Little Secrets, is available on Amazon, along with her companion field journal, Explore Outdoors, at Amazon.com/author/ pamelabaxter.