Purple Tannia
Xanthosoma violaceum
Purple Tannia (Xanthosoma violaceum), also known as purple yautía or blue taro, is a striking variety of Xanthosoma distinguished by its vivid violet-purple corm flesh and dark purple-tinged petioles. While botanically closely related to common tannia (X. sagittifolium), its dramatic purple coloration sets it apart both visually and nutritionally — the deep purple flesh is rich in anthocyanins, powerful antioxidants that give this tropical root crop an extra nutritional dimension.
• Distinguished from common tannia by the vivid purple coloring of its corm flesh and leaf stalks
• The purple pigmentation indicates high levels of anthocyanins, the same antioxidants found in blueberries
• Sometimes classified as a variety of X. sagittifolium rather than a separate species
• Known as "malanga morada" (purple malanga) in the Spanish Caribbean
• The purple flesh retains its color when cooked, creating visually striking dishes
• Cultivated since pre-Columbian times in the Caribbean and Central America
• Widely distributed throughout the tropical lowlands of Central and South America
• Particularly important in the Dominican Republic, Cuba, Puerto Rico, and coastal Colombia and Venezuela
• Introduced to West Africa and tropical Asia through historical trade routes
• Often grown alongside common tannia in traditional mixed planting systems
• Less commonly cultivated than X. sagittifolium but prized in specific regional cuisines
• Genetic diversity is highest in the Caribbean and northern South American region
Leaves:
• Large, sagittate (arrowhead-shaped), 40 to 90 cm long
• Dark green blades on long petioles
• Petioles are dark purple to greenish-purple, a key distinguishing feature from common tannia
Corms:
• Medium to large, cylindrical to irregularly globose, 15 to 25 cm long
• Skin is brown and rough, similar to common tannia
• Flesh is the defining feature: vivid violet-purple to deep magenta throughout
• The purple color is due to high concentrations of anthocyanin pigments
• Starchy and dense, with a slightly nutty flavor when cooked
• Produces side cormels (small tubers) around the main corm
Plant Size:
• Total height 1 to 1.8 meters
• Forms clumps from produced cormels
Flowers:
• Typical aroid spathe and spadix; pale yellow to creamy spathe
• Flowering is uncommon in cultivation
• Per 100 g cooked corm: approximately 115 to 135 kcal
• High in complex carbohydrates (approximately 26 to 30 g per 100 g)
• Moderate dietary fiber (approximately 4 to 5 g per 100 g)
• Rich in anthocyanins — the purple pigments with powerful antioxidant and anti-inflammatory properties
• Good source of potassium (approximately 450 to 500 mg per 100 g)
• Contains phosphorus, magnesium, and iron
• Provides vitamin C, vitamin E, and small amounts of B vitamins
• Low in fat and protein
• The anthocyanin content gives it additional health benefits compared to white-fleshed varieties
• Gluten-free
Toxic Compounds:
• Calcium oxalate raphides present in raw corms and leaves
• Causes intense burning and irritation of mucous membranes if eaten raw
Safe Preparation:
• Peel and boil, bake, or fry for at least 15 to 20 minutes
• Cooking destroys calcium oxalate crystals completely
• Some traditional recipes call for soaking in acidic water before cooking to further reduce acridity
Planting:
• Propagated from cormels or corm tops
• Plant 7 to 10 cm deep, 60 to 90 cm apart
• Plant at the beginning of the rainy season
Growing:
• Requires hot, humid tropical conditions
• Prefers partial shade to full sun with moist, fertile soil
• Takes 8 to 10 months to produce harvestable corms
• Benefits from mulching to retain soil moisture
• Less widely adapted than common tannia; prefers more consistent moisture
Harvest:
• Harvest when leaves begin to yellow, 8 to 10 months after planting
• Dig carefully around the plant to extract corms
• Cormels can be harvested progressively
• Store in cool, dry conditions for 1 to 2 months
Culinary Uses (always cook thoroughly):
• Boiled and mashed — the purple color creates visually stunning purple mashed "potatoes"
• Fried into chips and fries with a distinctive violet hue
• In the Dominican Republic, grated for pasteles and other traditional dishes
• Added to soups and stews where it adds both thickening power and dramatic color
• In Puerto Rico, used in "mondongo" (tripe soup) and "sancocho" (hearty stew)
• Sometimes processed into a naturally purple flour for baking and desserts
Other Uses:
• Ornamental value in tropical landscaping for its purple-stemmed foliage
• The anthocyanin-rich flesh is studied for potential health food applications
• Used in traditional medicine in the Caribbean for digestive complaints
• Increasingly sought after by chefs for its unique color properties
Fun Fact
Purple Tannia produces mashed roots so vividly violet that they look like they've been dyed with food coloring — yet the color is entirely natural, caused by the same anthocyanin pigments that give blueberries their famous blue-purple hue.
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