Balloon Cotton
Gomphocarpus fruticosus, G. physocarpus
Apocynaceae
Medicinal.
A long lived perennial shrub growing from 0.5 to 2 metres in height. The stems and leaves contain a poisonous milky sap. Balloon Cotton or Narrow leaf cotton bush is poisonous to livestock and humans, and has caused deaths in cattle, sheep and poultry. Narrow leaf cotton bush reproduces by seed, however it can also sucker from lateral roots that are closest to the soil surface. The seeds are spread by wind and water, but can also be dispersed as a contaminant of agricultural produce, animals, machinery and other vehicles. Narrow leaf cotton bush is a common weed of grasslands, open woodlands and disturbed areas. It competes with native plants in these habitats and is capable of forming dense thickets. It is capable of resprouting following damage and is reported to have allelopathic properties.
Balloon Cotton is a host for the lesser wanderer butterfly (Danaus chrysippus petilia) and the Monarch butterfly (Danaus plexippus) - larvae feed on the plant, while adults obtain nectar from the flowers. Aphids are reported to infest this plant. Overseas, vespid wasps are attracted to the flowers. A common vespid wasp in Australia is the Paper wasp. While adults Paper wasps feed on nectar, they catch caterpillars and other small insects to feed larvae. In a study looking at phytopasmas hosts, it was reported that the diversity of phytoplasmas detected in G. physocarpus suggests it is a feeding source for phytoplasma insect vectors or it has a broad susceptibility to a range of phytoplasmas (Streten). Various insects are known to visit flowers and lady beetles have also been observed Balloon Cotton.