I saw a lovely plant today but didn't get a picture. They looked like purple snap dragons on a very dark purple stem, but a google search doesn't find them... any idea what they could be if not a snap dragon?
Certain types of snapdragon can have purple stems,such as the liberty or purple lavender varieties.If you google purple lavender snapdragon ,you will see a picture,may be what you saw.
I think it must be fairly common - I've got loads of snapdgragons grown from a generic pack of seeds 'Snapdragons - perfect for children' and quite a few have purple stems and purple edged leaves. Some even have leaves with bright pink edges!
It was as snapdragon, as the others say they do this themselves - you never see them separated out so I guess it is just luck whether you get the coloured stems and leaves. Some people may not like them I guess, the lemon ones seem to stay green, so maybe it is just the pink/purple ones that 'leak' thier colour.
We bought some dianthus recently, and several of those also had the purple stems, but not all, though they were all shades of red and purple flowers - just the way they go I think.