Chicory (Cichorium intybus, L. 1753)

Identity

Chicory (Cichorium intybus L., 1753), also called common chicory, is an herbaceous perennial in the genus Cichorium, family Asteraceae. The binomial Cichorium intybus identifies the ancestral species of most cultivated chicories, from witloof to radicchio and coffee chicory. ^{1 2}

Chicory cultivation dates to antiquity: Pliny the Elder already described it in his Natural History as a vegetable with many uses. Its roasted root has served as a coffee substitute for centuries, a use that becomes especially prominent during coffee-bean shortages. ^{8 4}

Recognition

A basal rosette of toothed to deeply lobed leaves forms first, resembling a dandelion’s. Even at this stage, one feature helps distinguish them: chicory lobes point outward from the rosette, while dandelion lobes point toward its center. Later, chicory develops a stiff, upright, much-branched flowering stem 60 cm to 1.5 m (2–5 ft) tall. ^{3 4}

Upper leaves are much smaller than basal leaves, lack stalks and clasp the stem directly. When cut, chicory releases milky latex from a thick, light-brown, fleshy taproot. ^{4 5}

The characteristic sky-blue flowers, occasionally white or pink, reach 4 cm (1.6 in) across. They open in morning sun and close in early afternoon or rainy weather. Each head blooms for one day only, replaced the next day by a new bud higher on the same stem. ^{2 3}

Useful taxonomy

Carl Linnaeus described this species in 1753 as Cichorium intybus L., still its accepted name. Cichorium, a small genus of Mediterranean and Eurasian species, belongs to the Cichorieae tribe of Asteraceae, alongside lettuces and dandelions. ^{1 7}

Cultivated forms often carry botanical variety names, distinct from ordinary trade labels:

• Cichorium intybus var. foliosum (Hegi) Janch., the witloof group that produces white heads;
• Cichorium intybus var. sativum Gaudin, the group grown for coffee roots;
• Cichorium intybus var. endivia (L.) Mérat, a name sometimes confused with true endive, a distinct species;
• Cichorium intybus subsp. pumilum (Jacq.) Ball, a smaller Mediterranean subspecies.

The accepted name, Cichorium intybus, remains the reliable reference: horticultural groups such as witloof and radicchio are selections, rather than separate species. ^{1 2}

Habitat and range

Chicory’s native range spans Europe, Central Asia and the western Himalayas, with extensions into Macaronesia and North Africa. Mainland France lies within this native range, where the species remains very common. ^{1 5}

Favored habitats include roadsides, waste ground, banks and dry to moderately moist grasslands, often on limestone or compacted soils that its deep taproot can penetrate. ^{6 5}

Naturalized widely in North America since colonial times, Cichorium intybus mainly occupies roadsides and disturbed ground there, without invading undisturbed natural habitats. Colorado lists it locally as a regulated noxious weed, a status that does not apply to its native range. ^{4 6}

Life cycle and reproduction

As a perennial, Cichorium intybus first forms a rosette in its initial year, then develops a flowering stem and reaches maturity in one to two years, depending on conditions. The rootstock subsequently regrows from the taproot each spring. ^{2 6}

Flowering extends from May to October in the Northern Hemisphere, from late spring into fall. Heads open in the morning, attracting many pollinating insects before closing in the afternoon. After pollination, each head produces small dry achenes dispersed by wind or animals. ^{3 2}

In gardens, seed sown directly in spring to early summer (April to June in the Northern Hemisphere) germinates in one to two weeks. Some root selections can also be propagated by root cuttings. Witloof makes particular use of this root: lifted in fall and forced in warmth and complete darkness, it produces new crisp white shoots, or chicons, within a few weeks. ^{5 2}

Uses and risks

Food is the primary use of Cichorium intybus. Its root is rich in inulin, up to 40% of dry weight, and has been roasted as a coffee substitute for centuries. Young leaves are eaten raw in salads or cooked, often blanched to reduce bitterness. ^{5 7}

Chicory also appears in traditional medicine for digestive, diuretic and liver-related uses. Recent studies report a reassuring safety profile, with no sign of notable toxicity in rats, while reiterating the usual caution for people allergic to the Asteraceae family. ^{7 5}

As forage, chicory proved too coarse for routine grazing. Trials with sheep nevertheless show a strong reduction in egg shedding by the parasite Haemonchus contortus, attributed to the bitter sesquiterpene lactones lactucin and lactucopicrin. ^{6 7}

Varieties, look-alikes and related plants

Cultivated forms are selections from the same genetic pool, rather than separate species. Witloof, or Belgian endive, comes from a dark-forcing technique developed in Belgium in the 19th century: a root forced in warmth without light produces a crisp white head. Italian radicchio, with purple leaves packed into heads, and sugarloaf chicory, with elongated, less bitter heads, illustrate the same horticultural diversity. ^{2 5}

Plants frequently confused with chicory include:

• Taraxacum, dandelion, whose young rosette resembles chicory’s, but whose flowering stalk stays single, hollow and unbranched, unlike the stiff, much-branched stem of Cichorium intybus;
• Cichorium endivia, true endive, a separate species grown for its leaves and sometimes confused with witloof because of the shared common name.

Sky-blue flowers, a much-branched stem and basal leaves with outward-pointing lobes remain the most reliable features for confirming Cichorium intybus. ^{3 4}

Main sources

• Plants of the World Online / Kew, Cichorium intybus L.
• Royal Horticultural Society, Cichorium intybus - chicory
• Missouri Botanical Garden, Cichorium intybus
• University of Wisconsin Extension, Chicory, Cichorium intybus
• Plants For A Future, Cichorium intybus
• Utah State University Extension, Chicory, range plants
• Traditional uses, phytochemistry, pharmacology and toxicology of Cichorium intybus
• Pliny the Elder, Natural History, Book XX, on intybus