Somehow last year I grew radicchio. I must have accidentally picked a bag of Radicchio di Treviso (or trevisano) seeds or decided that I'd give radicchio a try while I was at the garden center, and then forgotten about it. Fact is that last spring, as I was starting my garden, I found this bag of radicchio seeds in my gardening basket. I sowed it, and waited to see what would happen.
It grew pretty fast: thick, hairy green oblong leaves, very bitter in taste (or "toxic", as my children say).
It kept growing during the summer, impervious to the neglect my garden suffered while my family and I were on the road (here), and to disease and bugs (even the snails that happily feed on my lettuce did not seem to have a taste for its "toxic" leaves).
Note: there are milder varieties of radicchio, such as the rounder radicchio di Chioggia
Towards the end of August, my radicchio di Treviso started turning red, as the night temperatures began to drop, and thereafter it thrived in the cooler weather: the leaves became thinner and more palatable, and the taste milder.
And it continued to do well during the winter, which was long but not terribly cold, with only two hard frosts and a couple of snowstorms.
After the snow melted, I just removed the spoiled outer leaves, and the healthy heads kept on growing and producing radicchio red lettuce leaves.
So, we had fresh radicchio throughout the winter. Thinly sliced in salads (balsamic vinegar does wonders to mellow out its pungent taste), or sliced length-wise and grilled or roasted.
As the temperatures rose again in April, our radicchio started turning greener and becoming more bitter in flavor, and I pulled it up: during a one-year cycle, it had produced impressively deep, strong roots, considering it was lettuce.
It was great to have fresh radicchio from the garden during the winter, and I'd recommend it to anyone who has enough garden space, especially those who live in less favorable climates.