Posted: 19/06/2015 at 07:43
I find that with foxglove seedlings, the all green ones produce pale flowers, and the ones with a reddish hue to the leaf petioles produce purple flowers. Young cosmos plants are similar, green stems lighter colour flowers, stems with a red flushing give darker pink or red flowers. If you have a lot of young plants, you can rogue them at that stage before waiting for flowers. I hope that helps.