Rose of Sharon

I believe it's a Hibiscus :)

We also call Hibiscus syriacus= Rose of Sharon in Canada. I've noticed someone on this site called Hypericum calycinum =Rose of Sharon. That was news to me Hywel. Common name of Hypericum on this continent is St. John's wort .
Pretty confusing.

That's why I prefer calling plants by their botanical names ...

Hypericum calycinum is what we call Rose of Sharon here.
Hypericum perforatum is called St John's Wort.
There are other Hypericums but I think they are just called 'Hypericum'

We just call Hibiscus 'Hibiscus'

The name hibiscus is reserved for the beautiful large flowered tropical plant here which we cannot grow here outside. I grow one indoors. But I agree with you completely, the best is to use botanical names. Less confusing .I inherited Hibiscus syriacus with all white flowers. It is almost a small tree now. Quite beautiful.
I see them in garden centers.... mainly the purple ones and they do have Rose of Sharon labels on them (bellow the latin name)

Different countries, different customs :-))))X

Makes it all the more interesting :) x

Rose of Sharon and Hibiscus are close relatives and both originate from Asia (China) with Rose-of-Sharon in the higher elevations and hardier. Chinese hibiscus (Hibiscus rosa-sinensis) and the rose-of-Sharon (Hibiscus syriacus) add bold visual interest to a garden. These two species are close relatives -- both are members of the mallow family, Malvaceae. Horticulturists and breeders developed numerous cultivars of both shrubs, increasing the number of ornamental plants with particularly showy flower colors.