I was scanning Ebay to see what cold hardy citrus was listed. While scanning I ran across this seller offering a hardy blood orange. Knowing blood orange is zone 9 citrus I had to contact and ask what zone where these bood oranges for and this was his reply.
Dear will2358,
Thank you for contacting us. This blood orange tree can thrive in USDA Hardiness Zone 4. If you have any other question or concern, don't hesitate to contact us.
Kind Regards,
Of course I had to respond back. Sellers like this ruin it for the good honest sellers. My goodness he went down to zone 4.