Will Sweet William flower Nov/Dec?

No - Sweet William is biennial, so the idea is that you buy it as bedding in the autumn, which is its first year, plant it out, and it flowers next spring/early summer(2nd year).

They can flower for 2 or 3 years so don't just pull them up after flowering. Sometimes they don't flower until their 3rd year!!

I've got sweet williams in the garden that flowered this year. I was thinking of pulling them up when I tidy up as I thought that was them done - but they have been putting on quite a lot of leaf growth..... I have already emptied the ones out of pots unfortunately. I shall now leave them in and see if they flower again next spring.

Thanks for your replies they have helped a lot, I think it is a beautiful flower and will get some ordered. I was thinking of putting them in the border of my front garden do you think this will look right or are they a little tall for borders? Thanks.

No, not too tall - just don't put them too close to the edge - they don't get that tall anyway.