Prairie Ground Cherry (Physalis hederifolia), a nightshade family member from the southwestern USA and northern Mexico, and a regionally controlled or prohibited weed throughout much of Victoria where it is an occupier of paddock and cropland.
Ground Cherry seeds are spread in the droppings of stock, foxes and birds, and roots can also be transported and regenerate at other locations. The fruit itself is also moved by wind and water, and seeds in fruit buried whole can apparently persist in the ground for 20 years.
Although not in itself a commercial crop, it is possible that Prairie Ground Cherry was introduced unintentionally to Australia among other varieties of Physalis with commercial potential. Newspapers from the end of the 19th century and beginning of the 20th contain a number of accounts of ground cherry seeds being distributed at farmers’ meetings and exhibited at agricultural society shows around Australia.
The species was first recorded naturalised in Australia near the Murray in 1913, when it was collected at Cohuna VIC by the newly minted State Government Plant Pathologist C.C. Brittlebank. By 1923, Prairie Ground Cherry had shown up within the metropolitan at Werribee; it was declared under the Noxious Weeds and Vermin Act in 1929. Despite control efforts, it spread to SA by 1950.
Today the heartland of the infestation remains country Victoria, with a second population running from the outskirts of the metropolitan west up through Bacchus Marsh. Atypical of that pattern, the plants photographed form a local infestation on pipeline track running parallel to the M80 north of Fawkner, with additional individual plants located separately along the M80 trail about 1 km to the west. The species has been recorded in the vicinity since 2011; excepting two collections from vacant industrial sites in Flemington and Footscray in the 1990s, this is the principal recorded infestation inside of the Western Ring Road.
This form of infestation, inhabiting legacy paddock and infrastructural space, is almost surely present on other restricted access sites in the clayey north.