Well, for what it's worth, a marigold managed to self-sow in my California poppy patch, and is blooming.
I'm having to cover it with a box covered with a plastic bag at night because it's rainy and getting down to freezing during the nights; I want to collect it's seeds.
The California poppies are just little sprouts right now.

I'm guessing everything is ice cold and frozen, without bloom or leaf, in Scotland at this time?