Like its close cousins in the endive group, all about radicchio varieties are members of the Chicory family. Radicchio has been in cultivation since the fifteenth century in Veneto, a region in the northeast of Italy. Most radicchio varieties are named according to the area within Veneto where they were popularized: Treviso, Chioggia, Castelfranco, and so on.
(The Chioggia group are the familiar red & white, round heads.)
It’s no surprise that radicchio’s strong Italian heritage has left it something of a stranger in the wider world of vegetables we know from northern Europe and the New World. But, like the gradual popularization of pac choi and gai lan from east Asia, radicchio is beginning to make itself known in the home garden.
Radicchio can be an expensive supermarket item – when you can find it fresh in the first place – but it’s very easy to grow. It can be planted in the spring or fall, direct sown or started indoors and transplanted out in early April, and again in late July into August. Summer harvested radicchio has a slight nutty bitterness that some people love, but harvested in the fall or winter, the flavour is much milder, even with a hint of sweetness.
Radicchio needs to be spaced about 30cm (12”) apart in order to mature fully. The root system is shallower than those of its endive cousins, so they benefit from regular, though not deep, watering. Uneven watering in hot weather can increase the bitter flavour of the leaves. The outer leaves fall away from the centre, much like a head lettuce, and then a solid cabbage-like ball forms at the plant’s heart. The plants are biennial, so if this head is cut cleanly from the stem, just above ground level, it may produce a second one. Being cold hardy, plants may simply producing all winter in mild years.
The outer leaves are perfectly edible, but it’s that interior core that is most prized. It can be blanched by placing an inverted pot over the plant (even a paper bag can be used), or in the case of Treviso, the outer leaves can be bound at the top, forming a tight cocoon in which the heart can blanch. Taking this extra step increases the whiteness of the veins and the overall sweetness of the final product.
Well that’s all fine, but how does one use the stuff? Radicchio makes a fine addition to salads, adding colour, flavour, and crunch, but it can also be roasted, grilled, sautéed, braised or stir-fried. Chop a head into quarters, drizzle them with olive oil, and sprinkle them with chopped garlic. Then grill on the barbecue until they are heated through, tender, and slightly charred. It’s unbelievable!
Cooked or raw, radicchio combines extremely well with crumbled cheese, dried fruits, and nuts. Use an acid like lemon juice or balsamic vinegar to awaken the flavours. Both the round and columnar radicchio types make visually striking and practical “scoops” or “bowls” for canapés such as smoked salmon, ricotta, and fresh dill. Lively flavours seem to bring out the best of radicchio.
There are five principal types of radicchio. The most common and familiar is Radicchio di Chioggia, which has a spherical shape, intensely red leaves, and bright white veins. Cultivars of this variety include Palla Rossa, and Rossa di Verone. Chioggia (pronounced “kee-OH-gee-ah”) is an island town located south of Venice. It is also the ancestral home of the red and white striped Chioggia beet.
Perhaps the second best known type is Radicchio di Treviso, which grows with an upright, football-like shape. The petioles (stems) are longer, more pronounced, and have a distinctive succulent and tangy taste. This is one of the most popular varieties in Italy, and is recommended as a grilled vegetable. Cooking reduces the plant’s natural bitterness somewhat, and results in a very unique and tasty side dish. Treviso is the name of both a province in Italy and its capital city.
Radicchio di Castelfranco has big, soft, creamy yellow leaves specked with red. It grows into a voluptuous lettuce-like ball and then unfolds from the centre like an opening rose. The leaves are tender and flavourful, and some of the best for raw eating in salads. Once again, this raddichio is named for a town northwest of Venice – Castelfranco Veneto.
(Radicchio di Luisa has primarily green leaves, with subtle red speckles.)
Radicchio di Puntarelle and Radicchio di Tardivo are less familiar, and much rarer, even in good specialty markets. The prized heart of Tardivo looks something like a red and white octopus. Puntarelle is even stranger in appearance, resembling a clump of fennel bulbs topped by asparagus stems. Both of these require more work to produce, as they result from forcing and blanching like Belgian endive.
(Radicchio di Tardivo results from blanching Treviso in a particular way.)
So take the plunge and be adventurous. Grow some radicchio from seed in your garden, even if it’s only a couple of heads the first time. You’ll wish you had planted more, and you’ll probably work it into your annual vegetable plan.