Chinese Artichoke (Crosne)

Plant dormant tubers in spring, once the ground is workable, into a fertile, humus-rich, well-drained soil in full sun. On clay, work in organic matter before planting. Expect a full season of top growth before there is anything worth digging. The tuber is the whole plant's savings account: it has to push up a season of leaf, run the summer, and only then swell new tubers underground before frost. Planting in spring gives it that entire window, and loose, humus-rich soil is what lets the new tubers form cleanly instead of stalling in a compacted layer.

RHS lists division as the propagation method for this crop. Do it in spring, at the same point in the year RHS gives for planting tubers: lift a congested clump, break it apart, and replant the firmest tubers into refreshed soil at fresh spacing. Save your best tubers at digging time and use them as next spring's planting stock. This is a perennial that reproduces from its own tubers, so a patch left alone gets crowded and the tubers get smaller as they compete. Dividing resets the spacing, and because every tuber is a viable plant, your harvest and your seed stock are the same thing.

As the shoots come up in spring, check them for slug damage - ragged holes and grazed stems, worst after rain. Clear damp hiding places near the row and pick slugs off in the evening. The plant is otherwise generally disease-free and needs no spray program. Slugs are the one pest this crop reliably has, and they hit it hardest at emergence, when the soft new growth is the only leaf the plant owns. Shoots lost in spring are leaf area the plant never gets back, and leaf area in summer is exactly what pays for the tubers you dig in autumn.

Start digging once the season's top growth has finished, from late autumn onward. Lift only what you plan to eat and leave the rest of the patch in the ground - the tubers hold perfectly well in the soil over winter and can be dug as you need them. The tubers only reach size at the very end of the season, so digging early just costs you yield. The ground itself is the best storage this crop has: the plant is hardy well below -20C, so the tubers sit safely in cold soil and stay in the condition they were grown in.