artichoke artichoke blossom blossom botanic cook cooking field flower food fruit gardening globe artichoke leaf leaves nature plant summer vegetable vegetables appearance bracts budding cluster cultivar cultivated cynara-cardunculus distinctive edible-plant edible-portions flower-buds flower-head French-artichoke fresh globe-artichoke green-artichoke inflorescence petals produce raw shape surface surfaces tender-heart texture textured textures thick thin thistle-species tips tough-exterior uncooked unusual varieties ripe artichokes healthy bloom purple flowers globe plants delicacy garden head rosette spines spiny England Great Britain old sky stem Sussex