Like all members of the milkweed family, the balloon plant (Gomphocarpus physocarpus) is one of the best plants for attracting monarch butterflies. This unique shrub, which reaches heights of 4 to 6 feet (1-2 m.), is also known by a long list of alternate names including balloon cotton bush, family jewels, Oscar milkweed, goose plant, and swan plant to name just a few.
I. Appearance and Characteristics
Gomphocarpus physocarpus, commonly known as hairy balls, balloon plant, balloon cotton-bush, bishop’s balls, nailhead, or swan plant, is a species of plant in the family Apocynaceae, related to the milkweeds. The plant is native to southeast Africa, but it has been widely naturalized as it is often used as an ornamental plant.
Gomphocarpus physocarpus is an undershrub perennial herb, that can grow to over six feet. The plant blooms in warm months. It grows on roadside banks, at elevations of 2800 to 5000 feet above sea level. The plant prefers moderate moisture, as well as sandy and well-drained soil and full sun.
Its propagation can be done by seeds or by cuttings. To propagate through seeds, sow the seeds in a light, well-drained substrate. To propagate by cuttings, cut a branch about 10 cm long and remove the leaves at the base. Plant the branch in a pot with light, well-draining substrate.
Gomphocarpus physocarpus is traditionally used to produce ointments for the treatment of warts and the seeds are used in rituals. The leaves and stems produce milky latex that is toxic, yet it has never been described in detail particularly with regards to the anatomy of lactiferous cells.
The flowers are small, with white hoods and about 1 cm across. The follicle is a pale green, and in shape an inflated spheroid. It is covered with rough hairs. It reaches three inches in diameter. The leaves are light green, linear to lanceolate and 3 to 4 inches long, 1.2 cm broad. The brown seeds have silky tufts.
This plant will readily hybridize with Gomphocarpus fruticosus creating intermediate forms.
Balloon plant exudes a milky white latex that is toxic if ingested. All parts of the plant contain this latex, which can be exposed if they are damaged or broken. Though it is usually safe to handle balloon plant, exposure to this latex could cause some problems. An upset stomach is a primary symptom for those who ingest the latex. Proceed with caution when handling this plant because some people have recorded rashes and itching after skin contact with the latex. Keep children away to avoid accidental ingestion.
II. How to Grow and Care
Sunlight
Balloon plant thrives in conditions where it can receive full sun exposure as this intensity of light promotes vigorous growth and optimal health. Its ability to tolerate partial sun means that while it can adapt to somewhat lower light levels without significant detriment, its optimal performance is observed with ample sunlight. Deviations from full sun may lead to less robust growth and fewer blooms. When grown outdoors, balloon plant should be placed in a location where it will receive unfiltered sunlight for the majority of the day. Adaptations such as leaf orientation may occur to maximize light absorption. However, it is not typically cultivated as an indoor plant.
Watering
Originating from regions with intermittent rainfall, balloon plant has adapted to make efficient use of available moisture, exhibiting moderate drought tolerance. This species thrives when watered every week, maintaining a balance between hydration and drainage. Ideally grown outdoors due to its preference for full sun exposure, balloon plant flourishes in well-draining soil which aids in preventing root rot – a common issue in overwatered specimens.
Fertilizing
For healthy growth, balloon plant benefits from fertilization that’s high in nitrogen. Apply a diluted, high-nitrogen liquid fertilizer monthly during spring and summer, as these growing seasons demand more nutrients. When fertilizing balloon plant, use roughly 1/4 to 1/2 strength of the recommended dosage to avoid overfeeding, which can harm the roots. In the dormant winter months, cease fertilization to prevent unnecessary stress. Ensure even distribution around the plant to promote consistent nourishment. Regular fertilizing will encourage balloon plant to develop robust stems and vibrant blooms while maintaining overall vigor.
Propagation
Balloon plant is most effectively propagated by sowing seeds during Spring. Success is indicated by emerging seedlings, and to ensure optimal growth, maintain appropriate moisture and temperature levels during germination.
Transplanting
Transplanting balloon plant thrives ideally when done during the delightful time of late spring to early summer, as warmer temperatures ensure successful root establishment. Choose a sunny or partially shady location that provides adequate air circulation. Gently loosen the root ball for better growth when necessary, and watch balloon plant flourish in its new environment.
Repotting
Balloon plant thrives best when repotted every 2-3 years, ideally in spring to support its vigorous summer growth. This bush-like plant requires a spacious pot to accommodate rapid development. Post-repotting, use a container that is one size larger to ensure root comfort. Ensure ample sunlight and moderate watering for balloon plant after repotting to promote recovery and robust growth.
III. Uses and Benefits
The balloon plant is generally grown as an ornamental for its unusual-looking fruit, which are yellowish and balloon-like. It is also chosen for its quick growth and clusters of multicolored, orchid-like vanilla-scented flowers. In gardens, it is generally used in mixed beds and containers, or as the backdrop plant for a mixed border.
