Mashua (Tropaeolum tuberosum) Is A Vibrant And Hardy Perennial Tuber Native To The Andes, Gaining Popularity Among UK Gardeners For Its Beautiful Flowers, Edible Tubers & Resilience In Cooler Climates.
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Often grown as an annual in the UK, mashua is relatively low-maintenance and can thrive here with the right care. Here’s how I grow it successfully.
Why Grow Mashua?
Edible tubers with a peppery, radish-like flavour
Ornamental value – attractive climbing vines with bright flowers
Pest-resistant – rarely troubled by diseases or insects
Nitrogen-fixing – enriches your soil
Planting Location and Soil
Mashua prefers a sunny or partially shaded spot with well-drained soil. It can tolerate a range of soil types but performs best in fertile, slightly acidic to neutral soil (pH 6–7). If your soil is heavy or clay, add organic matter such as compost or well-rotted manure to improve drainage.
When to Plant
Plant mashua tubers in mid to late spring, after the last frost has passed. In most UK regions, this means April to May. Tubers are widely available from specialist online suppliers – planting tubers rather than seeds is recommended for reliable results. In the south west I now overwinter them in the soil. Provided they are well covered they should be fine except in the very worst of frosts.
How to Plant
Dig a hole 5–10 cm deep.
Place the tuber horizontally and cover with soil.
Space tubers 30–40 cm apart.
Provide support such as a trellis, fence, tree or obelisk – mashua is a vigorous climber.
Watering and Feeding
Water newly planted tubers well, then keep soil consistently moist but not waterlogged. Once established, mashua is relatively drought-tolerant. Avoid overwatering, especially in heavy soils.
At planting time, mix a handful of compost or general-purpose organic fertiliser into the soil. A single feed at planting is usually sufficient – too much nitrogen can encourage leafy growth at the expense of tubers.
Pest and Disease Management
Mashua is largely pest-resistant, but young shoots can attract slugs and snails. Use organic deterrents such as beer traps.
In wet summers, I’m told we should watch for powdery mildew on leaves – ensure good air circulation and avoid overhead watering. To be fair this has not been a problem for me to date.
Care Through the Season
Summer: Train vines onto supports. Mulch around plants to retain moisture and suppress weeds.
Late summer to autumn: Plants will (usually) produce striking orange or red flowers. Tubers begin to swell from September onwards.
Harvesting
Tubers are ready to harvest after the first light frosts, usually from late October to November. In my case the ones in the image above were harvested in January … we have had few cross here to date! Frost enhances their flavour. To harvest:
Carefully dig around the plant with a fork to avoid damaging tubers.
Lift the whole plant and gently remove tubers.
Leave some smaller tubers in the ground to regrow the following year if desired.
Storing and Using Mashua
Brush off soil and store tubers in a cool, dark, frost-free place – they can last several months if kept dry. If any start to chit I put them in a pot and start them early with a little frost protection. They are then planted out once frosts have passed. Mashua can be eaten raw in salads, roasted, boiled, or added to stews. The leaves and flowers are also edible.
Overwintering
In milder UK regions, mulch heavily over the tubers left in the ground for winter protection. In colder areas, lift and store tubers indoors, replanting in spring. See above.
Final Tips for Success
Don’t overfeed – mashua thrives in moderate fertility.
Provide strong support – vines can reach 2–3 metres.
Grow with companions such as beans or nasturtiums for a productive, attractive plot.
Mashua is a rewarding and unusual crop for UK gardeners – offering beauty, resilience, and a tasty harvest with minimal fuss. Given a sunny spot, some support, and a little patience, it rewards me with a vibrant and productive plant and a crop of unusual tubers.
Grau, A., Ortega, R., Nieto, C., & Hermann, M. (2003). Mashua (Tropaeolum tuberosum Ruiz & Pav.). In: Promoting the conservation and use of underutilized and neglected crops. International Plant Genetic Resources Institute (IPGRI). The definitive scientific profile on mashua agronomy.
National Research Council (1989). Lost Crops of the Incas: Little-Known Plants of the Andes with Promise for Worldwide Cultivation. National Academies Press. Details mashua’s pest resistance, nutritional value, and traditional uses.
Royal Horticultural Society (RHS). (2023). Unusual Vegetables. RHS Advisory Services. Provides UK-specific climate and cultivation advice.
Food and Agriculture Organization (FAO). Andean Roots and Tubers. Covers post-harvest handling and storage of Andean tubers.
Heritage Seed Library (Garden Organic).Mashua Factsheet. – Provides practical trial results from UK growing conditions.
The European Cooperative Programme for Plant Genetic Resources (ECPGR).Documentation of Andean Roots and Tubers Database. – Contains agronomic data on planting and environmental requirements.
Any suggestions for purchase of tubers?
I bought my first batch from Incredible Veg. Tell Mandy I sent you!