Apium graveolens var. rapaceum.
The most unjustly snubbed vegetable of the North American garden — and yet one of the most delicious and useful, and one of the great forgotten stars of Central European and French cooking. Under its alien-looking knobby, bearded exterior, celeriac hides a white flesh of exceptional flavour: at once that of common celery (since it's the same species, Apium graveolens) and a deeper character, lightly nutty, almost perfumed. The Giant Prague variety (introduced in 1871) takes its name from the Czech capital and is a marker of celeriac's ancient importance in Bohemian and Germanic cooking, where it has gone for centuries into the great winter soups, the simmered gulasch stews and the root purées that form the backbone of Central European peasant fare.
In France, it's the star ingredient of céleri rémoulade, that Parisian bistro classic: raw celeriac grated into fine julienne, bound with a mustardy mayonnaise — served year-round as aperitif, starter or cold-meat side. The wild ancestor, marsh celery (smallage), still grows along European coasts and was already mentioned by Hippocrates and Pliny the Elder; through patient selection by medieval Italian and French gardeners, the modern cultivated forms were extracted — first stalk celery, then around the 16th century the bulbous-rooted celeriac.
A modest plant, 30-40 cm tall, with dark-green celery foliage (usable as a herb in the same way as regular celery leaf), which forms at the base a big, rough, irregular ball studded with little side roots — 10-15 cm across at full maturity (a fine specimen can weigh 800 g to 1.5 kg). Cream-pearly white flesh under brown skin.
Cooked, the texture turns melting like a potato, the flavour rounds out and loses any potential bitterness. Cubed in soups and cream soups (a celeriac-apple-thyme velouté is a revelation for anyone who's never tried it), puréed on its own or fifty-fifty with potato, in a gratin with cream and nutmeg, roasted in oven quarters with olive oil, garlic and herbs, in homemade fries cut into sticks, or raw, finely grated as rémoulade. Excellent too in mirepoix — it replaces or complements the classic celery in the foundational French aromatic base (onion, carrot, celery).
Grower's tip: Celeriac is one of the most demanding vegetables to start, with a very long season that often outstrips the patience of the novice gardener. Start indoors 10-12 weeks before last frost — from late February for a mid-May transplant. Seeds are tiny and slow to germinate (14-21 days), and germinate in light: don't cover them with soil, just press them into the surface. Keep the medium constantly moist through germination and the first growth phase. Transplant once all frost risk has passed, into a very rich soil that is particularly cool in water — celeriac needs constant moisture all season. To get well-rounded rather than fibrous roots, hill the base lightly mid-season and avoid all water stress. Harvest at full maturity before hard frost, but celeriacs left in the ground a little past the first light frosts develop even better flavour (the starches partly convert to sugars). Excellent storage: 4-6 months in a cold, humid root cellar (0-2 °C, 90-95% humidity).
- Open-pollinated. Heritage variety pre-1900. Biennial; flowers in the second year. Insect-pollinated; crosses with stalk celery (all Apium graveolens) — isolate for seed saving.
- Height: 30-40 cm for the foliage.
- Maturity: 100-120 days after transplant.
- Exposure: full sun; part shade tolerated in summer.
- Very rich, deep, water-cool (essential), well-drained, neutral soil. Space plants 25-30 cm apart.
- Start indoors 10-12 weeks before last frost (late February in Québec). Don't cover seeds (need light to germinate). Transplant mid-May. Fall harvest. Excellent in the root cellar.
