I am very pleased with the radicchio I have this year. Even though only one in five plants headed, one head goes a long way. And its a beautiful red in our salads.
Most of my radicchio bolted - probably because the season warmed up so fast. My Chinese cabbage (Wong Bok), which is supposed to be a big head, didn't head at all. Just big furry leaves and then bolted into a big flower stalk. It made for lots of fresh greens for the compost pile. My savoy and red cabbage didn't have any trouble with the weather though. The savoy heads are ready for harvest, the reds will need a few more weeks.
This radicchio variety is Palla Rossa Ashalim (Botanical Interests) planted from seed on March 23. From the drawing on the seed package, it seems it should be a round head. Maybe my elongated heads are from the warm weather.