Mashua

Tropaeolum tuberosum is native to the Andean highlands of South America.

• Cultivated from Colombia to Bolivia, with greatest production in Peru and Bolivia
• Grown at elevations of 2,500 to 4,000 meters
• Has been cultivated for at least 1,500 years, likely much longer
• Was an important crop of the Inca Empire
• Pre-Columbian farmers valued its natural pest resistance, often intercropping it with potatoes and oca
• First described by the Spanish botanists Ruiz and Pavón in the late 18th century
• Rarely grown outside the Andes, though it has been introduced to New Zealand and Europe
• Over 100 landrace varieties exist in the Andean highlands
• Recently gained attention as a potential climate-resilient crop for high-altitude tropical agriculture

A climbing or trailing perennial herb growing 2 to 4 meters long.

Stems:
• Slender, green to purplish, twining, climbing over other plants or supports
• Smooth, somewhat succulent

Leaves:
• Peltate (shield-shaped, stem attached at the center), 3 to 8 cm in diameter
• Bright green, rounded to slightly lobed, with 3 to 5 lobes
• margins entire to slightly lobed
• Long petioles, 5 to 15 cm

Flowers:
• Showy, bisexual, 2 to 3 cm long
• Reddish-orange to scarlet with a long, spurred calyx (like nasturtiums)
• Five petals, the upper two often smaller
• Born in leaf axils

Tubers:
• Conical to spindle-shaped, 5 to 15 cm long
• Colors include white, yellow, orange, red, and purple, often with darker markings
• Skin smooth, thin
• Flesh yellow to orange, firm
• Pungent, peppery flavor when raw, milder when cooked
• Form at the base of the stem and along stolons

Tropaeolum tuberosum plays a unique ecological role in Andean highland agriculture as a naturally pest-resistant intercrop.

Habitat:
• Native to the Andean highlands of South America from Colombia to Bolivia, at elevations of 2,500 to 4,000 meters
• Grows in cool, moist mountain conditions with annual rainfall of 600 to 1,200 mm
• Tolerates light frosts and brief freezing; performs poorly in hot, tropical lowlands
• Prefers well-drained, humus-rich volcanic loam soils on terraced slopes
• USDA zones 7–10 (cold-hardy, tubers survive ground freezing)

Growth Habit:
• Vigorous climbing or trailing perennial herb growing 2 to 4 meters long
• Climbs on supporting plants, fences, or trellises using twining leaf petioles
• Short-day plant — tuber formation triggered as days shorten in late summer and autumn
• Becomes dormant during the dry Andean winter, regrowing from tubers in spring

Pollination:
• Showy, orange-red, spurred flowers (typical of Tropaeolum) are primarily bee-pollinated
• Also visited by hummingbirds in the Andean native range
• Self-incompatible in many varieties — cross-pollination between different clones is required for seed set
• Seed production is rare in cultivation; propagation is almost exclusively by tuber division

Ecological Role:
• Exceptionally pest-resistant — glucosinolate compounds in all plant parts repel insects, nematodes, and mammalian herbivores
• Traditionally interplanted with potatoes as a companion crop — its pest-repellent properties protect neighboring plants from nematodes and tuber moths
• The strong smelling foliage is used as a barrier plant around field margins in some Andean farming systems
• Tubers left in the ground serve as a food reserve for Andean rodents and other small mammals
• Flowers provide a late-season nectar source for high-altitude bees and hummingbirds

Conservation:
• Over 100 landrace varieties maintained by indigenous Andean farmers, representing significant genetic diversity
• Very limited cultivation outside the Andes, though it has been introduced to New Zealand and Europe
• Considered an underutilized crop with high potential for food security in high-altitude tropical regions

Mashua tubers are nutritious and energy-dense.

• Per 100 g fresh tubers: approximately 50 to 70 kcal
• High carbohydrate content (11 to 14 g per 100 g) — excellent energy source for high-altitude farmers
• Moderate protein (1.5 to 2 g per 100 g)
• Good source of vitamin C (approximately 20 to 40 mg per 100 g)
• Contains potassium, calcium, phosphorus, and iron
• Rich in glucosinolates — the same antioxidant compounds found in broccoli and cabbage
• Contains isothiocyanates responsible for the pungent flavor and pest-repellent properties
• Low in fat
• Leaves are also nutritious, rich in vitamin C and minerals

Propagated by planting whole or sectioned tubers.

• Plant tubers 5 to 8 cm deep at the start of the growing season
• Space 40 to 60 cm apart in rows 80 to 100 cm apart
• Provide a trellis or support for the climbing stems
• Prefers cool temperatures (10 to 18°C) and high altitude or cool-season growing
• Requires well-drained, fertile soils
• Tolerates light frost; damaged by heavy freezes
• Keep consistently moist during the growing season
• Tubers form as days shorten in autumn
• Harvest after foliage dies back, typically 180 to 220 days after planting
• Exceptionally pest-resistant; rarely needs pesticide treatment
• Tubers store well for several months in cool, dark conditions
• The vining habit makes it suitable for intercropping with corn or other tall crops

Culinary uses:
• Tubers are typically boiled, baked, or roasted — cooking reduces the pungency
• In Peru and Bolivia, boiled mashua is eaten with cheese and chili sauce
• Used in traditional Andean stews and soups
• Can be fried like potatoes, with a unique peppery flavor
• Some varieties are eaten raw as a sharp, radish-like snack
• Made into chuno (freeze-dried tubers) for long-term storage
• Leaves are cooked as a potherb, similar to nasturtium leaves
• The peppery flavor pairs well with robust cheeses and meats
• In some Andean communities, mashua is fermented into a beverage