Salvia

We bought these salvias in the garden centre and they didn't do much for ages. Now they've suddenly flowered, blue and powdery-looking. As they're in a pot they're getting watered, so should flower well I think, although the others we have in the garden are surviving the drought well at the moment too, without help. And the tomatoes and chillies don't mind the heat at all so long as they're kept well-watered. Courgettes however are a bit of a mystery- they look healthy enough, but have stopped growing and the fruits don't get more than about four inches long before they stop too. I'm not sure whether it's too much heat or perhaps insufficient food, but I've never come across it before.