Walla-Walla Onion Giant Walla-Walla Mammoth Onion Is So Sweet, Crisp and Juicy. Challenge The World Record Of A 7 1/2 Pound Onion Giant Walla-Walla Onion rivals the Vidalia. Our mammoth onion is the biggest and best flavored we could find! In taste tests held in Georgia, home of the Vidalia onions, our Walla-Walla proves to be a strong contender. Sometimes Vidalia wins on flavor, and sometimes Walla-Walla - but Walla-Walla is consistently BIGGER and unlike Vidalia (which grows in only 2 counties), Giant Walla-Walla will successfully grow in every state. Grow A Record Breaking Onion. We send you plants, not seeds or sets which will give you the biggest bulbs. Plant them at 12"" intervals; maturity begins 65 days planting. Sorry this item cannot be shipped into Idaho