VegetableBean
Shironata Mame Sword Bean
Shironata Mame is a distinctive Japanese sword bean variety prized for its snow-white seeds, a trait that sets it apart from the red-seeded sword beans more commonly seen in Asian gardens. This vigorous vining annual reaches 12 to 17 feet tall and produces pods ready to harvest in just 80 to 89 days, making it well-suited to gardeners in zones 3 through 9 who want an heirloom snap bean with genuine cultural roots. The variety thrives in full sun with moderate water and performs admirably in containers, raised beds, and traditional garden plots, offering both practical yields and the satisfaction of growing a specialty bean with historical significance.
Photo © True Leaf Market
Growing Conditions
USDA Zone
3-9
Sunlight
Full Sun
Water
Moderate
Soil
Well-drained, Fertile Loam To Sandy Loam
Growth Stats
204 in
Height
TypeVining
Spacing
36
Plant Profile
Sunlight
Full Sun
Water
Moderate
Zones
3-9
Size
204in H x ?in W
Growth
—
Care
High
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Highlights
The 'Shiro' (white) coloring of these seeds carries real cultural weight in Japanese agricultural tradition, distinguishing this cultivar from its red-seeded cousins and marking it as a distinct heirloom worth preserving. Its status as an open-pollinated, non-GMO variety means you can save seeds year after year, anchoring it firmly in the slow-food and seed-saving movements. The plant's flexibility across growing environments, from containers to traditional garden beds, combined with its impressive 144- to 204-inch height, gives gardeners genuine options for how they integrate it into their space.
Common Uses
As a snap bean, Shironata Mame is eaten fresh from the pod when young and tender, a preparation common in Japanese cuisine and throughout Asian cooking. The whole immature pods can be steamed, stir-fried, or added to soups. The mature white seeds, once dried, transition into a different culinary role entirely, suitable for bean soups, traditional dishes, and applications that take advantage of their distinctive pale color and texture.
Growing Timeline
No timeline data available yet for this variety.
Care Instructions
Direct Sow
Direct sow seeds into the garden when soil temperature reaches 70 to 85 degrees Fahrenheit and all danger of frost has passed. Plant at the base of a sturdy trellis or support structure, as the vines will grow vigorously to 12 to 17 feet tall.
Harvesting
Harvest immature pods when they are tender and snap cleanly between your fingers, typically 80 to 89 days after sowing. Pick snap pods regularly to encourage continued flowering and production. For mature dried beans, allow pods to remain on the vine until they turn brown and papery, then harvest and shell out the distinctive white seeds for drying and storage.
Pruning
As a vigorous vining variety, Shironata Mame benefits from consistent training onto a sturdy trellis or support system. Guide the main vines upward and prune any side shoots that grow away from your support structure to direct energy into vertical growth and pod production.
Growing Calendar
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Companion Planting
Pests & Diseases
Ecology & Traits
Edible
Scientific Classification
Canavalia gladiata
Family
Fabaceae
Genus
Canavalia
Growth Habit
Vining
Native Status
VI (I)
History & Origin
“Shironata Mame carries the history of Japanese heirloom beans, where the white seed color has been deliberately maintained and valued across generations. The 'Shironata' name itself encodes this heritage, with 'Shiro' meaning white in Japanese. Both red and white sword beans have deep roots in Japanese agriculture and medicinal plant traditions, suggesting this variety was selected and preserved not merely for yield but for qualities valued within specific cultural contexts. Its journey from Japanese gardens to seed catalogs today reflects the growing interest in preserving regional heirloom vegetables and making them accessible to home gardeners worldwide.”