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.
Zenjeff, that's the double cultivar whose name escapes me. The species is much more like the OP.