It is a biennial so it will grow from the seeds for next year but they only flower if the seeds become good -sized plants before winter . It may well have self seeded already but you can scatter the seeds from the silvery pods or grow them in pots if you want to. Then cut down the untidy plant after that. The seeds are not mature when the pods are green ; they need to go silvery but I am sure that will have happened by now.

Strude, when the pods are silvery, the seeds have already dropped off--the silvery part is actually the membrane between the two seed chambers in the pod. The pods are ready to harvest when the green starts to turn brown or tan, which is when you pick them and put them into a paper bag to dry, shatter, and release their seeds. If the pods are already all silver, don't despair: you probably already have strong young seedlings coming up in the bed--and where you don't want them, as well! : )

I agree,you will have lots of seedlings appearing next year...easily mistaken for weeds when they first appear..similar to a nettle leaf..but they won't flower till the following spring..that is,if you want them all !!

Thank you for responses, I grew the honesty from seed and I did think they were weeds when they started growing, nearly dug them up again! The seed pods aren't silvery yet, still a tan colour so the seeds must still be intact. I'll pull them up and put them in a paper bag to dry as Tugbrethil suggested.

If you can, I would put some stems intact in an oversized paper or cloth bag, and hang them upside down, so when the seeds are shed, you can enjoy the silvery ovals in dried arrangements through the winter.