?Cardoons

Decided to move my cardoons which spent the summer leaning over a main path, scratching innocent passers by. For plotholders are well-armed and shoot from the hip, or in this case, chopped off my exquisite cardoons' purple heads. Became clear getting to the root of the probem was a tough job, but undeterred my spade and I heaved and dug and suddenly up one came, then another. Roots torn and broken, but with cans of water and beds of mixed compost, manure and leaf mould they are now rehoused. One new shoot broke right off. A, who knows his plants, told me to cut the outside leaf down to the tip of the heart of the new leaves and pop it in since it had a hint of root. Followed instruction and left it looking perky. Strange to think these prickly giants began as seeds on my window ledge. I call them cardoons because my usually knowledgeable plotmates do, but I thought the seed packet (now lost) was entitled more glamorously, artichoke "violetta di Chioggia". What is the identifiable difference?