"Next time RTFM."

Hmm.. Yes, as helpful as comment as that is, I was more interested generally in why the spray might not be a good idea for some plants.

"It may well be because it will mark the flowers."

Ah. I'll have to test that out in the summer. So far, the foliage looks fine (apart from the aphid corpses..). I imagine when they're planted outside the mildew problem will sort itself out.

I do hope they're not awfully invasive, or I'll have to have words with Thompson and Morgan for the lack of warning.