Chinese Artichoke: Sowing, Growing and Harvesting

Description and Botany

The Chinese artichoke (Stachys affinis syn. tuberosa), also commonly called Japanese artichoke or knotroot, is a root vegetable from the Lamiaceae family, characterised by quadrangular stems and terminal spike flowering, like mint, lavender, catmint…

Botanical illustration

It is a perennial vegetable plant, grown as an annual in our climates, with running rhizomatous roots. Originating from Asia, mainly China, and cultivated in Japan, this herbaceous plant was introduced to Europe in 1880, then cultivated by botanist gardeners in Crosne, a town now located in Essonne, southeast of Paris. In 1882, Nisolas-Auguste Paillieux was the first to distribute this vegetable in French kitchen gardens. It quickly appeared in market gardens and on greengrocers’ stalls at very reasonable prices.

The term “stachys” comes from the Greek “stachus” meaning “spike” while “affinis” comes from the Latin “adfinis” meaning “related, similar”. The plant is also found under the Latin name Stachys tuberosa, tuberosa referring to the shape of its cylindrical strings.

The Chinese artichoke produces tuberous roots, composed of nodose strings of fine, fleshy ringed tubercles. These tubercles measuring 5 to 7 cm are covered with an exceptionally thin creamy white skin. Chinese artichokes have a very delicate flavour between artichoke and salsify, slightly enhanced with a taste of roasted hazelnut and Jerusalem artichoke. They are eaten cooked.

This fast-growing herbaceous plant forms a clump 30 to 60 cm high, relatively dense and compact, with a spreading habit. It therefore tends to flop. Moreover, it is branched in all directions, and has quadrangular stems bearing opposite, ovate, long-petiolate deciduous leaves. Slightly waffled and crenate at the edges, the leaves display a glaucous green colour. They are rough and measure 5 to 10 cm long by 2.5 cm wide.

Its flowering is very rarely observed in France. It occurs in midsummer, between July and August. The flowers are bilabiate, of a bright pinkish white. A line of more intense pink runs through the centre.

Leaves and flowers of Japanese artichoke

The rhizomes of this plant grown as an annual in our climates are hardy down to -15°C. However, the foliage disappears in winter.

Main species and varieties

Only the type species is cultivated here.

Stachys affinis

The Chinese artichoke is harvested when the foliage has disappeared, from November and throughout the winter

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Planting Chinese artichokes

Where to Plant?

Japanese artichoke tubercles should be planted in light, even sandy, dry and well-aerated soil. It should crumble perfectly. In terms of soil type, all varieties are suitable as long as it is light to facilitate harvesting. Heavy or clay soils must absolutely be lightened with sand. Indeed, in heavy soils, the artichokes, formed of balls stuck together, will be difficult to harvest and clean due to their small size.

A cool to slightly moist soil, rich in humus, will also suit them.

They prefer a sunny location but can tolerate partial shade.

© Frantz Vincentz

When to Plant?

Planting Japanese artichoke tubercles takes place, depending on the region, in March or April, or even February if the weather is mild. Beyond April, it is too late to plant them, even though artichokes benefit from rapid growth. Allow 7 to 8 months before the first harvest.

How to Plant?

Japanese artichokes are grown in ranks, much like potatoes, by planting tubercles:

• Work the soil with a fork to aerate it well and remove weeds and stones
• Mark out ranks spaced 35 to 40 cm apart
• Using a bulb planter, make holes 15 cm deep, spaced 15 to 20 cm apart
• Place 2 to 3 tubercles in each hole
• Fill in the hole without compacting
• Water.

You can also plant the tubercles in buckets under cover from February onwards. They will be transplanted into open ground in April.

Maintenance, Diseases and Companion Planting

Growing and caring for Chinese artichokes is not very difficult, although they do require some attention.

During dry weather and in case of drought, watering will be necessary. Otherwise, Chinese artichokes do not need water.

In May-June, it is recommended to hoe to remove weeds. Take the opportunity to earth up the young plants. Mounding soil around the clump will facilitate tubercle formation and prevent the plant from sprawling too much. The tubercles grow near the soil surface, so take care not to damage them.

Then, it is advisable to install good mulch, for several reasons: it will keep the soil cool and prevent weed proliferation. Similarly, as Chinese artichoke harvests are spread over a long winter period, the mulch prevents the ground from freezing too much. This makes harvesting easier. You can create your mulch layer, at least 20 cm thick, with straw and dead leaves, possibly mixed with well-dried grass clippings.

Like potatoes, Chinese artichokes can be planted alongside celeriac, cabbages, spinach, peas and beans.

Few pests are known to attack Chinese artichokes, apart from perhaps slugs which eat the young shoots.

Harvest and storage

When and how to harvest Chinese artichokes?

• The harvest: harvesting Chinese artichokes takes place from November onwards and throughout winter, until February, as and when needed. The foliage should begin to wilt before disappearing. This is why mulching is important, as it will help you locate the young plants. You can even add hessian sacks to insulate the rootstocks from the cold in regions with harsh winters. Harvesting is done by pulling up the young plants with a beak spade. The yield is in the order of 250 to 500 g per young plant in favourable soil. As the rootstocks are very resistant to frost, those forgotten in the soil will regrow the following year. You can also store some, protected from frost, in slightly damp sand, to plant from February until early April
• Storage: once out of the ground, Chinese artichokes are very delicate and soften quickly. They should be eaten very quickly, within 2 or 3 days at most.

Uses and Nutritional Benefits

Since it’s impossible to peel Chinese artichokes, the method to remove the skin involves rubbing them in a coarse cloth after washing. You can also scrub them with a small brush with very soft hairs. Then, simply rinse them in clear lemon water to remove any remaining epidermis.

Chinese artichokes are mainly eaten steamed, simply blanched for 10 minutes, or pan-fried. They can also be cooked as a gratin. They pair wonderfully with meats and game. In Japan, they are also eaten pickled in vinegar.

Chinese artichokes are rich in dietary fibre, essential for digestive system function. However, they contain stachyose which can make them hard to digest. They are also a source of plant proteins, and nutrients like potassium, calcium or phosphorus. They are also very nourishing and very low in fat.