Roots & Tubers

Oca

Oxalis tuberosa

A colourful Andean tuber with a lively tang raw and a softer nutty flavour once cooked.

Tuber cropTangy tubersCool-climate crop

Awaiting restock

Plants are grown on a small scale. The exact supplied size and format can vary with the season; when this item is available, the current sale details are shown here.

This plant is currently awaiting restock.

LifecyclePerennial (grown as an annual in the UK; harvest before frost and replant in spring)

PositionFull sun to partial shade

SoilLoose, fertile, well-drained soil makes tuber harvest easier. It also grows well in large containers.

Garden sizeGrows to about 30 cm tall, spreading 30 cm wide

ContainerMedium to large container (minimum 30–35 cm deep); prefers well-drained soil

Historic erasVictorian

Why it belongs in a forgotten garden

Oca — the story

Why grow it?

Oca looks like a decorative clover-like plant all summer, then hides the real prize underground: brightly coloured, tangy tubers formed late in the season.

History & context

A vibrant root crop from the Andes, Oca (Oxalis tuberosa) is a rewarding treasure with a zingy twist. This colourful perennial is gaining popularity in the UK as a low-maintenance, potato-like alternative that thrives in cooler climates. It rewards patience with a bright, delicious harvest that is well worth the wait.

Explore its place in Victorian garden history.

Growing guide

How to grow Oca

Soil & position

Loose, fertile, well-drained soil makes tuber harvest easier. It also grows well in large containers.

Light: Full sun to partial shade

Water

Keep watered through summer growth, especially in pots, but avoid permanently saturated soil.

Propagation

Plant seed tubers after frost risk has eased. It is propagated vegetatively rather than from true seed in normal garden practice.

Sowing referencePlant Apr–MayDepth: 5–7 cm • Cold treatment: No (tubers)

Ongoing care

Earth up or mulch around stems as plants grow. Protect from early autumn frost if possible because tuber formation accelerates as days shorten.

From garden to kitchen

Harvesting & eating it

When to harvest

Wait until frost has killed the foliage, then leave the tubers for roughly a week or two to finish swelling before lifting carefully.

Wait until late in the season: tuber formation increases as days shorten. Lift after frost has checked the foliage, taking care to find the small tubers around the plant.

What is edible?

Tubers are the main crop; leaves are also edible but contain oxalates and are not the reason most people grow it.

Flavour & cooking

The tubers have a tangy flavour when eaten raw that mellows to a delicious nutty taste when cooked. They are excellent roasted, boiled, or fried and are a fantastic addition to salads, soups, or as a vibrant side dish.

Food value

Tubers provide carbohydrate, fibre and vitamin C. Their sharpness is partly due to oxalic acid, which can be reduced by exposing harvested tubers to light for several days before cooking.

Traditional medicinal uses, where mentioned in the historical material, are included as history rather than medical advice.

Kitchen idea

Roast Oca with rosemary & honey

After a few days of light exposure, Oca becomes noticeably sweeter and roasts beautifully.

You’ll need

700 g Oca tubers, scrubbed
1½ tbsp olive oil
1 tbsp honey
1 tbsp cider vinegar
2 sprigs rosemary, chopped
½ tsp flaky salt
Black pepper

Method

Heat the oven to 210°C / 190°C fan.
Halve larger tubers and toss all the Oca with oil, rosemary, salt and pepper.
Roast for 25–35 minutes until golden and tender.
Mix honey and vinegar, drizzle over and return to the oven for 5 minutes.
Taste and add a little more vinegar if you want to emphasise Oca’s natural tang.

How tough is it?

Resilience, pests & garden value

Resilience

A surprisingly tough perennial, Oca is highly resistant to common pests and holds its own in a variety of conditions. It adapts well to cooler climates, making it a dependable, low-maintenance choice that rewards you with a colourful harvest.

Pests & practical problems

Relatively pest free. Slugs can damage foliage and tubers; the main challenge in Britain is getting enough frost-free autumn time for good tuber formation.

Wildlife value

Flowers are uncommon in some conditions; the dense summer canopy still provides habitat at ground level.

Growing in a container

Medium to large container (minimum 30–35 cm deep); prefers well-drained soil

Container plants generally need more frequent watering and feeding than the same plant in open ground.

Ready to grow it?

Oca