The common English names of these closely related plants is the cause of much confusion. Here, chicory is used for the green varieties of Cichorium intybus, while radicchio is used for those that display red colouration.
Both heading and leaf varieties are available and are growing in popularity in Australia. Mesculin (misticanza in Italian) salad typically has a few tired red leaves, which belies the potential contribution of chicory and radicchio to both salads and cooked dishes. Cichorium endiva has two variants, escarole endive (indiva scarola) and curly endive (indiva riccia). Defined by their distinctive taste, the use of these vegetables is increasing in Australia.
The best winter salad I have ever had was at Allsun Farm near Canberra and made from freshly picked radicchio and escarole endive tossed in a lemon juice and olive oil dressing. Another classic is radicchio and shaved fennel with an orange juice dressing. Delicious. Try Franchi radicchio rossa di Traviso in a risotto. Fantastic.
These vegetables all display some degree of bitterness which is beneficial to health in that it promotes appetite and the flow of gastric juices which improves internal body function. Campari, a favourite of mine, is an Italian aperitif, and has a distinct bitter taste intended to promote the appetite.
Chicories are deep rooted, unfussy plants.