Jean wrote: >> I'd also suggest botrytis, a fungal disease which *doesn't* require free water to infect plants I wanted to thank everybody who sent me advice, both on this list and privately. I should share the consensus feedback, in case you ever see something similar in your garden. It looks like this may have been a case of a mix of water stress and fungal infection. In other words, the pots probably got a bit dry in our hot spell, this caused weakness or the beginnings of dieback in the leaves, and the fungus jumped on that. The leaves have stopped dying back now, although I can't tell whether it was due to the fungicide I sprayed or the rainy spell we had this week. Thanks again, Mike San Jose, CA