I saw it in a planting outside a commercial establishment. It was about two feet tall, looked a bit like an airy bush, with thin, almost carnation like leaves and stems

Everyone I have asked has given me a different answer and when I look up what they say, it is not the same plant.

The location where I found it is about an hour away, so going back to ask someone would be quite an effort.

The picture was taken after it was in my car for two and a half hours, one hour of which was in 90 degree heat and it still held up.