Hibiscus trianum not H. richardsonii

NZ native hibiscus, annual or short-lived perennial. Easy as and a great choice as a filler in beds, pots and planters. It forms a mound of lobed, dark green leaves, flowers are 7cm across. Lemon with dark maroon centers. While each flower lasts only a single day, the plant blooms profusely all season. 

Abbie Jury has written about this species in one of her posts. It is well worth reading through any and all of her articles. I am unable to put the link in here, but just google jury

She  notes that this plants is probably not the native species but  it is only recently that it has been separated from a very similar species, now called H. richardsonii, which is truly indigenous and indeed critically endangered in its natural habitat of northern east coast areas. The two are probably crossed by now. I am sure this is a common one, not the special native species.