Rhubarb

Rhubarb is a hardy herbaceous perennial grown for its thick, fleshy stalks, which range from deep crimson to pale green depending on variety. It grows from short, thick rhizomes and produces large triangular leaves that are toxic due to their high oxalic acid content — only the stalks are eaten. Rhubarb thrives in cool climates and is exceptionally winter-hardy, making it well suited to Nordic gardens. Once established, a single plant can produce harvests for a decade or more.

Growing

Sow seeds 2 cm deep in trays or pots once soil reaches at least 5 °C. Seeds often benefit from brief cold stratification (1–2 weeks in a damp medium at 2–4 °C) before indoor sowing. Germination takes 7–20 days. Grow seedlings on indoors for 6–8 weeks before transplanting. Space young plants 10 cm apart at first; transplant to final spacing of 120 cm between plants and 120 cm between rows once large enough. Crowns can also be planted directly outdoors — set rhizome buds just at or slightly below soil level.

Care

Water consistently during dry spells, especially in the first year. Apply a balanced organic fertiliser or well-rotted compost around the crown each year once new growth begins. Remove flowering stalks promptly as they divert energy from stalk production. Mulch around the base to retain moisture and suppress weeds. Avoid harvesting any stalks in the first year to allow the plant to establish fully; in the second year take only a few stalks per plant.

Harvest

Begin harvesting when stalks are firm, well-coloured and at least 25–30 cm long. Grip each stalk at the base and pull with a slight twist rather than cutting, which encourages regrowth. Harvest over roughly 8 weeks once the plant is mature, always leaving at least 4–5 stalks per plant to sustain photosynthesis. Stop harvesting once stalks become noticeably thin, which signals the plant needs to rebuild reserves. Never eat the leaves.

In the kitchen

Rhubarb stalks are sharply sour and almost always cooked with sweetener. Classic preparations include compotes, jams, crumbles, pies, tarts and fruit soups. Rhubarb pairs well with strawberries, vanilla, ginger, cardamom and orange zest. It also works in savoury chutneys alongside pork or oily fish. Roasting stalks briefly with a little honey caramelises the surface and tempers acidity.

Storing

Fresh stalks keep for up to 2 weeks wrapped loosely in a damp cloth in the refrigerator. For longer storage, chop into 2–3 cm pieces and freeze in a single layer on a tray before transferring to bags; frozen rhubarb keeps for up to 12 months. Cooked compote stores in sterilised jars in the fridge for 2 weeks or can be preserved by water-bath canning.