This rhizomatous or stoloniferous perennial herb is naturalised on rough ground, rubbish tips, roadsides and waste places, usually close to habitation. Generally lowland, but recorded at 490 m above Garrigill (Cumberland).
This species was introduced into cultivation from Italy in 1683, and recorded in the wild by about 1730. It is still widely grown as a garden plant. It is certainly increasing in many areas.
A European Temperate species, absent as a native from much of W. Europe.