Butterfly Bush Seed

To collect butterfly bush seed do I wait untill the steam where the flowers were turns brown or just the floweres? The floweres are brown but the steam is still green.
Thanks

Ruth,
I have had several people say that just the deadhead flower is the seeds...but I think by looking at mine that when you leave them on there a little longer you will start to see little things that looks like grains of rice. I think that is the seeds. But maybe someone else can tell you better than I can. Try leaving one on there for a while and see if you start to see the grains of rice looing things on them.
I'll be sure and watch this, b/c I'd like to see what everyone else has to say also.
O BTW, What color is it?? I have noticed that the yellow ones dont have the "rice grains" on them, Was wondering if they seed off at all?!

Molly it is purple.

Mine is too Ruth, Try leaving one on there and see if you can see the little seed pods.

Just happened to be looking over this and I know the answer, even if it is late! LOL The rice shaped thing is actually the seed pod. On some, it will get close to half an long. It is filled with dust like lenghts, not even as thick as a human hair: those are the seeds. Someone once told me they look like helicopter propellers and they do! LOL They are extremely small, elongated and have a small mark in the center. I tried taking pics of them last year and no luck.

Thanks Badseed.

and if you dont deadhead, you'll have a gazillion seedlings... yup yup yup - couldnt for the life of me germinate butterfly bush seeds when I bought the seeds, but when i got a plant and forgot to deadhead, they were all over the place.....