I came across this little sweetie in an Omokoroa garden several years ago and was surprised to learn it was a “native hibiscus” as I always imagine hibiscus as large, tropical shrubs, not front-of-the-border temperate zone plants.
It’s generally classified as an annual, although in some places may be a two-year plant.
“Although rare in the wild, it naturalises freely from seeds in warm sites throughout the country, even in the southern South Island,” according to Alison Evans in New Zealand in Flower (get a copy from a book fair near you.)
“There is some evidence that Hibiscus trionum may have been introduced to New Zealand by Maori who used the leaves for cleaning hands and may have cultivated it for this purpose and for its attractive flowers.”
Fiona Eadie, in her book 100 Best Native Plants for New Zealand Gardens, reports that there are two very similar types of H. trionum in the country – one native (and which also occurs in Australia) and one that was introduced by man and has naturalised.
The difference, she says, is that the latter has more finely dissected leaves and an almost maroon centre, so I think I’m right is saying that the one pictured here is the true native … or am I? Keep reading.
Flowering is from late spring into autumn and the plant typically forms a small bush about 50cm high. It can tolerate very dry conditions which may even encourage flowering and doesn’t mind coastal winds – but it doesn’t care for very wet positions and frosts. It sets seed readily. Unfortunately, the flowers are no good for picking as they wilt immediately but the seed heads are liked by floral artists.
However, since the two books I’ve referenced were published (1987 and 2008 respectively) there has been a bit of a rethink on the “native” status of H. trionum, something I was alerted to by a recent post of Abbie Jury’s.
Shirley Stuart, curator of the native plants collection at the Dunedin Botanic Garden, has decided to treat H. trionum it as a “non-indigenous fully naturalised native” after doubts about its origins were raised.
The Oratia Native Plant Nursery website says of Hibiscus richardsonii: “Previously known as Hibiscus trionum this yellow-flowered Mercury Islands form is now recognised as the true native species.” Read a full profile of H. richardsonii which is now accorded the name “puarangi” previously given to H. trionum and which you’ll see is missing that dark centre.
Native or not, H. trionum is a pretty little thing that grows well and should be appreciated on its merits, not where it hails from.