Artichoke

Family

Asteraceae

Habit

perennial

Height

1.2 m

Spread

1.5 m

Growth

medium

Lifespan

8 years

First yield

after 2 years

Hardiness

zone 7–9

Shade tolerance

light shade

Soil

Sand, Silt, Loam

Soil moisture

semi-dry – very moist

pH

6 – 8

Times apply to the northern hemisphere in a temperate climate and shift with altitude and cultivar.

Edible: On large artichokes the edible parts are the fleshy lower portions of the bracts and above all the receptacle, the artichoke heart. The fine hairs above it, the "hay", are left behind. Small-headed cultivars picked early, such as the spineless Roman artichoke, can be eaten whole. Classically the heads are boiled 20 to 45 minutes in salted water with a squeeze of lemon, the leaves pulled off and the fleshy base drawn through the teeth — served with a vinaigrette. Whole heads are also fried or deep-fried, and the bottoms preserved in oil with herbs as antipasti or pizza topping. Boiled without seasoning, the flavour recalls the white of a fried egg. Per 100 grams it provides about 47 kilocalories, 10.5 grams of carbohydrate, 3.3 grams of protein, 5.4 grams of fibre and useful amounts of vitamins B9, C and K. Less well known: the peeled flower stems make a good vegetable too.

Other uses: The artichoke is more than a vegetable. Its flower styles act as a vegetable rennet and are used in Portugal and Spain to make cheeses without animal rennet, such as Serra da Estrela and Torta del Casar — one of the few traditional options for vegetarian cheesemaking. Artichoke oil pressed from the seeds serves as a culinary oil and as feedstock for biodiesel; on Sardinia a biorefinery processes the whole plant into bioplastics. In the garden the look counts as well: the silver-grey, deeply cut foliage and the head-high flower stems make it a lead architectural perennial, and the dried flower head lasts a long time as decoration.

Site: An artichoke needs room — up to 1.5 metres tall and as wide, with massive silver-grey foliage. In a vegetable bed it belongs on the northern edge, or it shades everything behind it; as a structural plant in a border that same habit is its strength. It wants full sun, warmth and shelter from wind on deep, humus-rich, free-draining soil. The real site question is winter: not the cold but standing wet at the rootstock kills it, so avoid hollows and compacted ground. Left to flower, it is one of the strongest bumblebee and wild bee resources of high summer. Wild forms carry spines on the bracts, so keep them away from paths and seating. Care: A hungry plant — generous compost in spring, then even watering, because drought stress makes the heads hard and fibrous. Harvest while the bracts are still tightly closed; the main head first, then smaller side heads follow. Cut the stems back after harvest and a second flush of leaves often appears. Winter protection is the critical part: leaves, brushwood and fleece over the rootstock plus a cover against rain; in cold areas lift the crown and overwinter it frost-free and dry. Aphids on the shoots, slugs on young plants and mice at the rootstock are the usual opponents. Renew from side shoots after three or four years.

Sowing works from February under cover: germination at 20 degrees in two to three weeks, then prick out, harden off and plant out only after the last frosts — the first year usually gives no crop. Seedlings vary, though, in head size as well as spininess. True-to-type propagation is purely vegetative: in spring detach the rooted side shoots, the offsets, with a piece of rootstock and plant them straight away. Dividing an older crown also works and is due anyway once the plant loses vigour after a few years. Division and offsets are also the safest way to keep a proven, winter-hardy provenance in the garden.

Let artichokes flower instead of cutting every head and they rank among the strongest insect resources of high summer. The large violet heads open in succession over weeks and supply abundant nectar and pollen; bumblebees are the most conspicuous visitors, joined by wild bees, hoverflies, beetles and butterflies. Reliable species counts for Central Europe do not exist for the artichoke, because here it is a crop plant without its own associated fauna; its value comes from the quantity and timing of bloom, not from specialisation. The seeds are eaten by finches, above all goldfinches. The dead hollow stems offer overwintering nest sites for stem-nesting wild bees — leaving them standing until spring doubles the benefit.

Notable: a silver-grey thistle that made a career as a vegetable; Castroville in California calls itself the "Artichoke Centre of the World", supplies about 75% of the US crop+holds an artichoke festival; since 1953 it has been the base of the Paduan bitter liqueur Cynar; in southern Norway it was grown for the king+the root protected in winter under a stone slab; Darwin described the escaped form as the giant thistle of the Pampas;

Mediterranean region. The wild form of the artichoke, the cardoon or wild artichoke, spans the whole Mediterranean from Morocco and Portugal across Spain, southern France, Italy and Croatia to Greece and Libya; Cyprus, the Canaries and Madeira may also be part of its native range. The globe artichoke is the cultivated form bred from it (var. scolymus). It is grown today mainly in countries with a Mediterranean climate — Italy is the largest producer, followed by Spain, France, Argentina, Chile, California and increasingly China. Outside that climate it has escaped and become a weed in Argentina, California and Australia; in Central Europe frost limits its spread.

The artichoke comes from open, summer-dry Mediterranean landscapes: fallow ground, pasture, roadsides and disturbed sites on deep, free-draining soil. Its annual rhythm is written for that climate — it needs about five months of cool growing weather, grows through the winter half-year and flowers in summer. It takes frost poorly, but frost alone is not the problem: winter wet is what rots the fleshy rootstock. Its natural site is therefore sunny, warm and rather dry in winter. In Central Europe it has no habitat in the strict sense; here it exists only in cultivation and in gardens where those winter conditions are recreated.