Balloon milkweed (Gomphocarpus physocarpus) provides Monarch butterflies with nectar-rich flowers, a place to lay their eggs, and a caterpillar food source, which helps them get through their entire life cycle.
Balloon Milkweed: Taxonomy and Description
The balloon milkweed plant (Gomphocarpus physocarpus, from the family Apocynaceae) is a shrub with clusters of tiny, waxy white flowers and light green, lance-shaped leaves. It has round fruits covered in tiny bristles that follow the blooms.
These look like hairy balls; thus, hairy balls milkweed is another name for the plant. It can grow to about 4 to 6 feet and thrives in warm climates.
The balloon milkweed’s other common names are balloon cotton bush and swan plant. This plant can be found across North America, South America, and South Africa.
Balloon Milkweed and Monarch Butterflies
Monarch butterflies and balloon milkweeds are so connected that the butterfly weed and other plants that attract Monarchs can’t compete. It’s almost as if milkweeds are exclusively made for Monarch butterflies.
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The adult female butterflies lay eggs on this host plant. The caterpillars munch on its leaves, and adults consume the nectar.
On the other hand, Monarch butterflies help with the pollination of milkweeds. Each time they perch on the plant and flowers, the pollen will stick to their thorax and wings. The Monarchs will then visit different other milkweeds and pollinate them.
In its essence, it’s a mutual exchange of resources. Milkweed benefits from pollination and butterflies benefit from the plants’ nectar and leaves.
Do Monarch Caterpillars Eat Balloon Milkweed?
The Monarch butterfly caterpillars consume various kinds of milkweed, like family jewels tree (Asclepias physocarpa), swamp milkweed (Asclepias incarnata), and balloon milkweed (Gomphocarpus physocarpus). It is the only plant monarch caterpillars consume, giving them the nutrition they need to develop into adult butterflies.
Planting Balloon Milkweed in Your Garden
While most milkweed species are fast-growing and rather tall (1 to 4 feet), balloon milkweed is not. This makes it ideal for planting in tiny areas or alongside pathways.
Although most milkweed species prefer well-drained soil, balloon milkweed is more tolerant of dry soil. Because of this, it is a wonderful option for gardens in regions with little rainfall.
Also, balloon plant milkweed blooms in the late summer or early fall and sometimes after the last frost, as the majority of milkweed species do. This plant prefers full sun. It can survive in various soil types, including sand and clay.
The most common way to grow balloon milkweed is from seed. You can purchase the seeds online or from a shop specializing in exotic seeds or plants for butterfly gardens. However, if you go with the seeds, you’ll have to deal with the germination process.
On the other hand, you can buy garden-ready plants, which are easier to grow. If you already have balloon milkweed, you can harvest the seeds in the fall. Split open a seed pod and extract milkweed seeds before they burst on their own.
Caring for Balloon Milkweed
The balloon milkweed needs at least 6 hours of sunlight each day to thrive. The soil should be dry to medium dry and easily permeable to water. This plant is suitable for USDA plant hardiness zones 8 through 10 and will thrive in poor, rocky soil and grow quickly in rich, slightly acidic soil.
This plant can take any level of care and thrive when given little or no attention. If left unchecked, it will self-seed and take over a space–sometimes uncontrollably.
Is Milkweed Invasive?
The balloon plant is a beneficial wildflower and is considered non-invasive. Still, this plant grows quickly and may overtake a part of your garden. Research a bit about its growing patterns to ensure it won’t take over your yard.
Joan is a nocturnal person who loves traveling and coffee. She’s also an animal lover (and rescuer) who makes it a point to befriend every animal she meets. Her passion for learning led her to writing about various topics. As someone who is a nature lover, she aims to continue learning about the wonderful creation—especially butterflies, and at the same time, share her knowledge here at Butterfly Hobbyist.