Calflora says it's 'rare'; actually it's rather extensively planted and doing as well as anything in these sad times.
I still have it coming up in my yard. 15 years ago I bought a few; and soon was faced with eliminating it or growing nothing else. It's remarkably difficult to extirpate, once established. Just way too vigorous and hugeous for your city garden.
Romneya (pronounced /ˈrÉ’mniËÉ™/) is a genus of flowering plants belonging to the poppy family (Papaveraceae). There are two species in genus Romneya, which was named for Irish astronomer John Thomas Romney Robinson. They are known commonly as Matilija poppies or tree poppies and are native to southern California and northern Mexico.