Iva Swingle Citrumelo

Iva Swingle Citrumelo is cataloged as a zygotic seedling selection of Swingle Citrumelo; The Mulberries reports that citrus breeder Alan Bishop selected it for improved fruit quality. Forum participants considered a Swingle-seedling origin likely from the tree, leaves and fruit, while the proposed surviving-rootstock origin near Iva, South Carolina, remains tentative. No pollen parent or molecular identity has been established.^{⁠[1]⁠[2]⁠[6]}

In the linked Iva/Bishop fruit review, The Mulberries report about 250 g and 12° Brix; the matching scorecard also prints pH 3.1. The video narrator's pH-strip estimate was provisional at ≤3, and the video describes moderate-to-low sourness and moderate sweetness while the card says low sweetness and labels sourness only “Sour.” The card and video concern the same fruit review, not separate samples.^{⁠[4]⁠[3]⁠[6]}

A northeastern New Jersey grower reported one unprotected winter observation on grafted Iva scions, including a single day at 0°F (−17.78°C) and about 200+ cumulative hours below freezing. The Iva graft on Swingle had foliage injury and some bark marking but no reported splitting or bleaching; the Iva graft on Poncirus looked better but was in less direct sun. This graft report does not establish a controlled survival threshold for mature trees. In a later post on October 24, 2026, raregrowsnj said all Iva grafts survived, but a Poncirus rootstock was damaged by an unspecified late freeze and repaired by bypass grafting. No temperature or duration was reported for that freeze.^⁠[6]

On October 23, 2026, hardyvermont reported 11° Brix from a green Iva fruit picked during a drought year, called it sweet and said no Poncirus flavor was perceived. The post gives no tree location, rootstock, replicate count, measurement method or physiological maturity; green appearance alone does not establish maturity.^⁠[6]