Gomphocarpus physocarpus

Common Name:
Balloon Cotton Bush
Swan Plant
Hairy Balls

Description:
Gomphocarpus physocarpus is a fast-growing, upright perennial shrub best known for its unusual inflated seed pods and clusters of small, waxy white flowers. The distinctive balloon-like pods give this plant strong ornamental appeal and make it a popular novelty addition to cottage gardens, pollinator gardens, and cut flower arrangements. In Melbourne, it grows best in a full sun position with well-drained soil and thrives through the warmer months, often behaving as a short-lived perennial or self-seeding annual depending on local conditions. The flowers are highly attractive to bees and butterflies, and the plant is especially valued as a host plant for monarch butterfly caterpillars. Its light, airy growth habit and curious seed pods add movement and interest to mixed borders and wildlife-friendly gardens. While decorative and useful for habitat planting, it should be positioned carefully, as it can self-seed freely in favourable conditions.

Form:
• Shrub - Medium

Mature Size:
• Height: 1.2–2 m
• Width: 80 cm – 1.2 m

Aspect:
• Full Sun

Flowering:
• Flowers in Spring
• Flowers in Summer
• Flowers in Autumn

Flower Colour:
• White
• Cream

Key Attributes:
• Suitable for Pots
• Bird Attracting
• Bee Attracting
• Herbaceous
• Perennial
• Butterfly host plant
• Excellent for cut seed pods
• Ornamental seed pods
• Fast growing
• Self-seeding
• Useful for wildlife gardens
• Can become weedy in favourable conditions
• Environmental weed potential in some areas

Toxicity:
Toxic if ingested. Like other members of the milkweed family, this plant contains milky sap and toxic compounds that may be harmful to humans, dogs, cats, and livestock if consumed. The sap may also irritate skin or eyes in sensitive individuals.

Companion Plants:
• Verbena bonariensis
• Salvia
• Gaura
• Cosmos
• Achillea
• Rudbeckia
• Echinacea
• Pennisetum