@Paul
I think that one of the things that makes ‘Shangjuan Lemon’ cold hardy is that it starts ripening fruits so much earlier than other varieties do. If only more citrus varieties would have ripe fruit at that time of the year, they would make great candidates for a cold hardy hybridization project.
I discovered the ‘Shangjuan Lemon’ variety because I was checking out what the nursery sells besides what I usually look for.
You can have ‘Fruitwood Nursery’ notify you when they are in stock, just in case they are selling it before you could find it from someone else.
I am not growing any cold hardy citrus right now, I did have some bitter orange seeds yet they never germinated.
I have loquat seedlings growing to use for root stock, I will eventually be testing different varieties of loquat in ground where I live, here it’s usually cold hardiness ‘zone 7b’ to ‘zone 8b’, yet occasionally it drops down to ‘zone 7a’ here. Many varieties of loquat can survive ‘zone 7a’, yet very few can actually fruit in ‘zone 7a’, some can though and that is why I will be testing. Also Someone located in NYC which is usually ‘7b+’ as well, will be testing loquat varieties in ground that I send them. Yet their winters being in the north east are different than our winters, so it will be interesting what they have for results. That same person in NYC will be testing varieties of fig trees in ground that I send them, same thing with pomegranates, all of which I grow in ground as well.
