[barbarella]

I have just finished cutting the sweet williams on my allotment and transplanted next year's seedlings.  I was wondering whether to dig up the remaining plants or if I might get a second flush this year.  Does anyone know?

[Trillium]

Sweet williams are mostly biennial, and if you've had the flowers, then they're finished for the year. But sometimes nature fools you and the plants turn perennial on you, so unless you really need the space, leave them to see what happens. I've had the same sweet williams on the same spot for years, and oddly enough, same with snapdragons which are 'annuals'. Go figure. 

[barbarella]

Thanks for that Trillium.  I once had wallflowers under a hedge and they came again for several years - I'm pretty sure they were the biennial ones, not the perennials. 

I haven't really got the room to leave the sweet williams to flower again next year so I will have them up and leave the new seedlings to do their stuff.