Visitors looking over my garden in the fall, always ask what the strange-looking plant is that is forming large spiny pods. Growing in my veggie garden, because of the amount of space the plants take, my Gymnocarpus physocarpa, or “Hairy Balls” are a conversation starter. A Milkweed family member, another common name is Balloon Plant. Native to South Africa, this plant is an invasive in tropical climates, but in my zone 6-7 area, winter cold keeps it in check.
Here are some facts about this amazing plant:
- Fast growing annual Milkweed, hardy in zones 8-10
- Can sustain lots of munching monarch caterpillars late season
- Nectar source for monarch butterflies
- Long stems with pods make beautiful table centerpiece
- Last viable Milkweed species before fall frost
- Start seeds at least 6-8 weeks inside; easy to germinate in about a week
- Flowers aren’t super showy, but still attractive
- Fewer pollinators use this than native Milkweed
- Pinch back the plant to make it bushier and with a stronger stem
- Place in the rear of a border as it can top off at 6 feet and may require staking
- The pods become ripe when they turn a tan color and burst open with the fuzzy seeds
- I save some seeds for planting in early spring in my greenhouse
Though some people have told me that monarch caterpillars have ignored their Hairy Balls, I found at least a dozen of them on my plants at once.
When all of my common Milkweeds are done, Hairy Balls Milkweed is going gangbusters into October and ending with our first hard frost. I have had these plants look good up to Halloween with active caterpillars. But be aware in colder climates, you need to start the seeds early.
Starting these seeds in my greenhouse in early March is essential to Hairy Balls producing the balloon shaped pods by the end of the summer. For most of the summer, these plants grow up and branch out and then August/September hits and the pods start to appear after a flush of small dangling flowers. I love watching the pods form!
For my monarch populations, this Milkweed is important as it still is standing with plenty of foliage late into the summer/early fall. My other common Milkweeds are totally denuded and finished when Hairy Balls hits its stride. For my post on other milkweeds, go to Got Milk….Weed? and Plant Milkweed for Monarchs.
Starting From Seed
I start my Hairy Balls from seed inside around mid-March to get a head start. The plants take a long time to form their wonderful seed capsules and I usually harvest from August on as they form.
Plant the seeds in good potting medium and cover about 1/4″ deep and the plants emerge in about 10 days. I keep them in the greenhouse until they reach about 4-5 inches high and the weather is warm enough- about the same time as tomatoes.
Once they are growing well in the garden, I usually pinch them to make them a little bit fuller and bushier. But if you don’t do this step, they still will grow fine.
When cutting the stems to use in arrangements, I torch the ends with my propane torch (or use matches) to stem the flow of milky sap.