Tamera plant growth looked very normal for Portugal (from the photos you posted on permies.) Paul was talking about a few inches of rain, and the reality is a few feet. That is a big difference ! I don't think even Extramadura is that dry. We are both closer to there, than Tamera, and yet we have a climate very similar to Tamera.
I would certainly be interested in seeing the book. You are very kind.
(Irises looking good by the way)