Osaka Purple Mustard Greens

Brassica juncea

Germination: 87%   (Packed for 2025)

Seeds per pack ~ 200

Origins and History

Osaka Purple Mustard (Brassica juncea) is a traditional Japanese heirloom green that reflects centuries of culinary and agricultural heritage from the Osaka region. Mustard greens themselves trace back to Asia, where they have been cultivated for thousands of years as both food and medicine. Osaka Purple developed as a local variety prized for its distinctive coloration and bold flavor, making it a staple in Japanese home gardens and markets. Its cultural importance lies in its dual role as a vegetable and as part of the diverse array of Asian mustards that spread across the globe through trade and migration.

Appearance and Characteristics

This mustard stands out for its broad, deeply veined leaves that range from deep green to a striking purple-bronze hue, especially in cooler weather. The leaves are oval to oblong with wavy or frilled edges, and the plant grows to about 12–18 inches tall. Its vibrant coloration and lush foliage also make it a favorite for ornamental edible landscaping. The flavor is sharp, peppery, and mustardy, becoming more pronounced as the plant matures.

Culinary Uses

Osaka Purple Mustard is highly versatile in the kitchen. Young leaves can be eaten raw, adding a spicy kick and splash of color to salads and sandwiches. Mature leaves are excellent in stir-fries, soups, and sautés, where cooking mellows their bite while retaining their earthy depth. In Japanese cuisine, they are often pickled or lightly braised. Their striking purple hue also makes them a beautiful garnish or component in mixed green dishes.

Growing Tips

This mustard is well-suited for temperate climates and thrives in USDA Zones 4–9. It prefers full sun but can tolerate partial shade, especially in warmer regions. Sow seeds directly outdoors in early spring or late summer for a fall crop, as it performs best in cooler weather. The recommended sowing depth is ¼ inch, with seeds spaced 2–4 inches apart, and thinning seedlings to about 6–8 inches as they grow. Plants benefit from rich, well-drained soil with consistent moisture to prevent bolting.

Harvesting Guidance

Leaves can be harvested young as baby greens in as little as 20–25 days. For full-sized leaves, allow 40–50 days to maturity. Harvest by cutting outer leaves and allowing the plant to continue producing, or by cutting the entire rosette at the base. For the best flavor and tenderness, harvest before hot weather sets in, as heat can cause leaves to turn more bitter and spur early bolting. Properly stored, freshly harvested leaves can last about a week in refrigeration.