The Walla Walla sweet onion is named for Walla Walla county in Washington where it is grown. Its development began around 1900 when Peter Pieri, a French soldier who settled in the area, brought a sweet onion seed from the island of Corsica with him to the Walla Walla Valley. This sweet onion was developed by selecting and reseeding onions from each year's crop that possessed sweetness, jumbo size, and round shape.
Other U.S. varieties
Imperial Valley Sweets come from the Imperial Valley in far southern California. This is one of the leading growing areas for sweet onions, although they are available only from late April through June.
The Carzalia Sweet onion is a variety of sweet onion grown by Carzalia Valley Produce in Columbus, New Mexico.
The Sunbrero (Texas) Sweet Onion is grown in Texas and distributed by Sweet Onion Trading Company, Melbourne, Florida.
The Sweetie Sweet is a variety of sweet onion grown in the Mason Valley in Yerington, Nevada. The Sweetie Sweet onion can be found in marketplaces throughout the September through the end of January.