Thunbergia gregorii

Wow! That's a surprising! This one is very common here in San Diego (with the many other species). It grows wild at the San Diego Zoo.

Frankly I'm gobsmacked as it wasn't a mild winter. It probably saw minus five in this sheltered area.

I always thought this species in particular wasn't hardy to below freezing. There's several species that will take just slightly below freezing without damage (depending on duration of temps below freezing).

The only thing I don't like about Thunbergia is that it is so extremely invasive and grows like crazy! (Thunbergia mysorensis is the exception) It can take over a huge area within a very short period of time. I've seen it take over a whole side of a house within a year and half.

"I always thought this species in particular wasn't hardy to below freezing."

Me too! I hate it when she proves me wrong. It is root hardy as opposed to growth hardy which I suppose make you and I half correct!

Oh, so it freezes to the ground and comes back in spring?

Yup! Even that surprises me though.

Many tropical plants if the roots don't freeze will come back in spring, though. The ground is a pretty good insulator.