Cichorium intybus .This pre-1700 Italian heirloom radicchio grows in an upright, columnar shape like a little urn. Pull away the lavish wrapper leaves to reveal a stunning red and white, blanched, sweet centre. Treviso is a cold hardy radicchio. Treviso chicory seeds produce plants that are beautiful in the garden. Radicchio will stand up to heat, and this heat brings out the sweetness and improves the flavour. The long stems (petioles) of this radicchio are crunchy and succulent.