60 Days to maturity. Allium fistulosum Ishikura Improved Bunching Onion Seeds. Annual, Non-GMO, Heirloom. This is a traditional medium early Japanese type bunching onion. At maturity, the stalk has white shanks up to 20-24" long with 6 or 7 deep green, thick leaves. These green onions do not form bulbs and do not multiply by division. The Ishikura Improved is tolerant to warm and cool temperatures and is suitable for winter harvesting in some areas. Approximately 7,000 seeds / oz.