They thrive in my garden, but they've finished blooming, and I know I'm supposed to cut the stalk with the spent flowers to encourage a second bloom. But I want the seed from that flower stalk, and it's still green, so I don't know whether the seed will be viable if I cut it now, or whether I have to wait until the stalk withers and turns brown before the seed will be viable. Anyone?

Second question: most of the stalks are the usual purple, but a few are white, and one is salmon colored. Will the seed be true to the color of the stalk? Will the seed from the stalk of white flowers produce white flowers again? Or is it a more complex Mendelian result?

Thanks!