Posted: 20/07/2017 at 17:53
You can sow them now, put in a cold frame and they will germinate when they feel like it in Spring.
Or you could sow as usual in March.
Sometimes they germinate better after being vernalised, i.e. exposed to the cold of winter before breaking germination.
They are one of those things that crop up where you didn't expect them, like cracks in paving.