If you live within 5 miles of the sea, but not on the East coast, and you're in a sheltered spot, then you could chance it - but otherwise no, I wouldn't risk it, particularly given the winter we had last year. Pot up into larger pots and keep under shelter for the winter, harden off and plant out early spring, depending on the weather.

Thanks for the reply, Bamboo. We were hit hard last winter so I'll take your advice - thanks again. Much appreciated.

Just having another thought ... I'm planning to plant out wallflower, forget-me-not, sweet william, winter pansies, polyanthus and bellis in the autumn. I have established wallflower & sweet william which come back every year but should new plants be overwintered in shelter for the first winter?

No, I'd plant those out, preferably early September to give 'em time to acclimatise before the weather gets cold - in London, that'd be early October, but you get colder earlier there.

Thanks again, Bamboo. So are Brompton Stocks the only half-hardy biennial? Any others I should watch out for?

All the ones you mentioned so far are hardy, although I have known sweet williams to be killed off in a really severe winter, but its rare.

Thanks again - so helpful.