Japanese Bunching Onions
Allium fistulosum
Tall, straight, blue-green leaves. Very resistant to bulbing and leaf-curl in the heat of midsummer. Long, white shanks provide excellent yields. Not as winter-hardy as Evergreen Hardy White.
Harvest
65d
Days to harvest
Sun
Full sun to partial shade
Zones
4–9
USDA hardiness
Height
1-3 feet
Planting Timeline
Showing dates for Japanese Bunching Onions in USDA Zone 7
All Zone 7 allium →Zone Map
Click a state to update dates
Japanese Bunching Onions · Zones 4–9
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | — | — | May – June | July – October |
| Zone 4 | — | — | April – June | June – October |
| Zone 5 | — | — | April – May | June – November |
| Zone 6 | — | — | April – May | June – November |
| Zone 7 | — | — | March – May | May – November |
| Zone 8 | — | — | March – April | May – December |
| Zone 9 | — | — | February – March | April – December |
| Zone 10 | — | — | January – March | March – December |
Complete Growing Guide
Soil: High Organic Matter, Loam (Silt), Sand. Drainage: Good Drainage. Height: 1 ft. 0 in. - 3 ft. 0 in.. Spread: 0 ft. 6 in. - 2 ft. 0 in.. Spacing: Less than 12 inches. Growth rate: Medium. Maintenance: Low. Propagation: Division. Regions: Coastal, Mountains, Piedmont.
Harvesting
The capsule splits longitudinally and contains small round black seeds.
Type: Capsule.
Bloom time: Spring, Summer
Storage & Preservation
Fresh Japanese bunching onions store best in the refrigerator, wrapped loosely in damp paper towels inside a plastic bag. They'll maintain quality for 7-10 days when stored this way. Avoid washing until ready to use, as excess moisture accelerates decay.
For longer storage, freezing works exceptionally well. Clean and chop both green and white portions, then freeze in portions on baking sheets before transferring to freezer bags. Frozen bunching onions work perfectly in cooked dishes but lose their crisp texture for raw applications.
Dehydrating is another excellent option – slice thinly and dry at 135°F until brittle, then store in airtight containers. Dried bunching onions rehydrate beautifully in soups and stews. You can also ferment the green portions in salt brine to create a tangy condiment popular in Korean cuisine.
History & Origin
Origin: Northern Hemisphere, North America and Eurasia
Advantages
- +Disease resistance: Deer
- +Low maintenance
Considerations
- -Toxic (Bark, Flowers, Fruits, Leaves, Roots, Seeds, Stems): Low severity
Companion Plants
Plant Together
Carrots
Onions repel carrot flies while carrots help break up soil for onion root development
Tomatoes
Onions deter aphids, whiteflies, and hornworms that commonly attack tomatoes
Brassicas (Cabbage, Broccoli)
Onions repel cabbage worms, flea beetles, and other brassica pests
Lettuce
Onions provide pest protection without competing for nutrients; lettuce shades onion roots
Peppers
Onions repel aphids and other soft-bodied insects that damage pepper plants
Strawberries
Onions deter slugs, aphids, and other pests that commonly attack strawberry plants
Roses
Onions repel aphids, thrips, and may help prevent black spot and other fungal diseases
Parsley
Compatible growth habits and onions help repel pests that attack herbs
Keep Apart
Beans
Onions can inhibit bean growth and nitrogen fixation by rhizobia bacteria
Peas
Allium compounds can interfere with pea growth and root nodule formation
Sage
Both plants compete for similar nutrients and sage can inhibit onion bulb development
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #170000)
Pests & Disease Resistance
Resistance
Generally disease resistant, very hardy
Common Pests
Onion thrips, aphids
Diseases
Downy mildew in humid conditions