Here in Christchurch, spring blooms appearing in yellow aren't just limited to daffodils.
One of New Zealand's iconic native species would have to be the Kowhai tree (pronounced ko - fai). I say iconic as a lot of people think it is NZ's national flower, but we don't actually have a national flower.
The blooms always appear in spring, often before the leaves emerge, yellow & cheerful. It is nice to see one this close to home when I am more used to seeing them outside of the city proper in this part of the country.