I'm saddened by the fear of the natural world.
It's not your fault Kev, the popular press love a good scare story. We don't really have dangerous animals in the UK but one incident makes a good story and takes precedence over real life.
easy in all I've tried but the cultivars (and most are cultivars) won't come reliably true.
Scary? it's a fox, not a lion
could we see a bit more of it please?
Brussels Sprouts are a type of cabbage
Watercress is Nasturtium officinale, it's a Brassica
But nasturtiums are Tropaeolum major, Tropaeolaceae family
(just to confuse things a little more)
that could be Nandina domestica but I've never seen one quite as yellow as that. It may be suffering from malnutrition.
pot it on.
4 plants in four different families is equally unlikely for rust. I have many plants with rust but all except one are Malvaceae.
and it doesn't look like rust.
Physical damage would be my guess.
not being hardy does not stop a plant being perennial. Protect it in winter and it's perennial. Lots of 'annual bedding' is tender perennials.