Scorzonera is a perennial plant of the Asteraceae family, with a long, fragile taproot that is black on the outside and white and milky inside.
The carbohydrate-rich, fleshy root is the most-used part of the plant.
Unlike most tubers and roots, its glucide composition is rich in inulin, which make it a good food for diabetics and those interested in a healthier diet. That unusual trait may make it a more highly sought after vegetable in the future, if it can become more widely known.
It is also said to have a very delicate flavor.
The plant is little cultivated outside of Europe, where it is mostly grown in Belgium, Poland, France and by members of the CIS.
It is highly prized by French chefs and used like potatoes in haute cuisine.
Scorzonera is native to the Mediterranean around Spain, where there are 13 species, although is presently not grown much there.
Cultivation of this plant is thought to have begun in 17th Century Spain. Its few stems grow to about 2 feet long, and if left in the ground after the first year, it bears yellowish flowers in spring and summer.
The tender, fleshy root is peeled and cut into pieces and placed in water with lemon to prevent it turning black. Then it is eaten in a variety of dishes.
It can be eaten raw in salad; dressed with vinaigrette or other sauces, steamed and served with Bearnaise or Bechamel sauce or with whole milk cream and toast; sauteed in butter with parsley or other herbs; boiled as an accompaniment to meat; grated with cheese; baked with tomato and roast mutton or pork; fried with oil or butter after being lightly cooked and served with lemon; scrambled with eggs or in omelettes; and preserved in sugar.
The leaves can also be eaten, especially if picked young and boiled. The very young leaves can also be eaten raw, and the shoots treated like asparagus.
Flowers are added to salads as a flavoring. They have a fragrance like cocoa. Flowers are also cooked in omelettes.
Scorzonera has similar cultivation requirements to white salsify and is typically grown as a winter vegetable, which though perennial is grown as an annual.
It is usually direct sown in early spring in shallow furrows a half-inch deep, spaced 2 to 4 inches apart, with rows 18 to 24 inches apart.
Birds like the seeds, so care must be taken to provide protection.
About 12 kg of seed per hectare is required. Scorzonera needs deep, fresh, loose soil rich in decomposed organic matter and free of stones or gravel, which cause root deformation.
Basal dressing is recommended at 30 tonnes per hectare of rotted manure, 50 units of N, 100 units of P2O5 and 200 to 250 units of K2O.
Scorzonera prefers sunny soils and easily assimilable nitrogen, of which an additional 50 units can be applied as a top dressing.
Many commercial cultivars exist, including Gigante de Rusia, with a very long and smooth root and very black skin and several selections derive from it; Lange Jan, good quality; Elite Stamm, productive and stable with high yield of superior size roots; Schwarze Pfahl, similar to Elite Stamm; Pronora, especially suitable for industrial processing; Vulcan, Duplex and Pilotis, suitable for frozen food industry; Hoffman 83, Flandria, Nero, Duro and Habil, good cultivars.
There are collections of local races and old cultivars at the Rijksstation voor Plantenveredling de Merelbeke (Belgium), at the Nordic Gene Bank in Alnarp (Sweden) and at the Vavilov Institute of Industrial Plants in St. Petersburg.
Harvesting takes place from November to March and requires perhaps more care than white salsify, as the roots are very fragile.
Furrows of about 40 cm must be opened parallel to the rows of roots. Yields of 20 to 30 tonnes per hectare have been obtained.
Lange Jan, Hoffman 83 and Flandria are the cultivars which have tested best for mechanical sowing and harvesting.
The most important diseases are mycosis, white rust, oidiopsis and strangulation and splitting of the roots, the cause of which is unknown.
Post-Harvest and Packing
Store at freezing or just below, for two to three months, or frozen with light industrial processing to clean, peel, cut and scald the vegetables to prevent oxidation.
Rich in carboydrates with a high proportion of inulin and laevulin, which makes it very suitable for a diabetic diet. It also contains conopherin (glucoside), asparagine, arginine, histidine and choline.