Has anyone here grown cardoon? I like the appearance of it in my garden (large thistle-like grey leaves), so have grown it for a few years. This year it went bonkers and is large and lush. I think you're supposed to tie the leaves together to blanch the center, but for how long? I don't have much time left before hard frosts. I may be out of time already if it got as cold this morning as I think it did. Thanks, Margaret