Nemesia hybrid cultivars (Nemesia cv.), growing as an infestation over a block and a half of East Melbourne.
Nemesia as a genus stems exclusively from Southern Africa, but it is widely grown in Northern Europe as a garden annual (species in the genus are variously annual or perennial, but frost tender). While a few of the annual Nemesia cultivars were available in early Melbourne, the hybrids seen here would be a more recent introduction.
N. floribunda is a recognised weed in New Zealand; Nemesia cultivars have been reported naturalised on roadsides in WA, and have been included on SA’s naturalised plant census since 2015. There have also been previous occurrence reports of adventive populations in TAS, QLD and NSW, going back to 1969. However, Nemesia does not appear to have been reported in a naturalised context in Victoria and has not been included in the Flora of Victoria.
In East Melbourne, in addition to a sequence of terrace yards heavily fronted with clumps of Nemesia, there are a number of plants that have established in pavement cracks in discrete positions remote from the main grouping, suggesting that the population is successfully spreading by seed in urban conditions.