Blue Morning Glory (Ipomoea indica), alien infestation of metropolitan Melbourne.
A pan-tropical plant of uncertain origin, Blue Morning Glory was sold in Melbourne from 1855 as a garden ornamental. Frost sensitive and limited to vegetative spread by stem fragment, the plant is rare outside of urban Victoria, but a common weed in coastal regions of NSW and QLD where there are botanical records of presumably naturalised specimens dating to the 1860s. In Victoria, the first botanical record apparently dates to 1958, and reports only became common in the 1980s.
The occurrence records for Melbourne provide an accurate picture of Blue Morning Glory’s limited range: ‘on a fence’, ‘urban wasteland’, ‘heavily weed invaded riverbank, under Schinus molle’. Its distribution is the familiar pattern of riparian edges, railway margins, vacant house lots and back lanes. However, those database records cannot capture the otherworldly, ‘colour out of space’ aspect of the plant’s dominance of those milieus; it is an alien botanical infection, concentrating ill-gotten saturation into useless flowers. How wonderful!