The difference is clear when the plants are mature, but this time of year, all that remains is the red seed heads. Is there something that can distinguish between jacks and greens when all there is left is a red seed head? So I know what seeds I have?

And also is there a difference between the seedlings of the two? I know jacks have one leaf the first year, and three the next. But what about the greens? I'm not sure if I have ever seen a green dragon seedling?