Zoia, you are right.
I went walkabout the other day to nosey into other people's gardens (from the street), and some had those red azaleas. In the yards of real old houses made of brick (laughingly called "redstone" or "brownstone" here). I was immediately on Google to find which ones. Most I found online are zone 7 and above though. So not for me. Not like I actually have the space, anyhow.
But they are a pretty thing to look at. Glad you shared that pic.