What do I need to do in the autumn to ensure my cardoon survives the winter? It was bought in a pot and planted out this summer. Thank you. Pam Franklin
If you live in a cold climate these plants are treated as annuals.
Here is a link with more information.
https://www.gardeningknowhow.com/edible/herbs/cardoon/growing-cardoon-plants.htm
I need to remove a mature Cardoon. I have dug out a lot of root, but it is fibrous, and DEEP. I would like to replant the area, and not sure which, or if any, rootkillers should be used.
You may need a nonselective herbicide containing glyphosate to kill the remaining roots. Be sure to read and follow all label instructions.
https://www.gardeningknowhow.com/edible/herbs/cardoon/growing-cardoon-plants.htm
https://www.gardeningknowhow.com/plant-problems/weeds/using-herbicide-in-gardens.htm