Sour tangerines???

I visited a friend yesterday (I'm in Florida), who showed me a backyard citrus tree I can't identify. The fruit, which was ripe now, appeared to be very small tangerines (the largest were the size of the "Cuties" commercially sold) but were extremely sour. The tree was maybe 20 ft. tall and rather old. I am fairly sure the original tree must have died and the more hardy rootstock has taken over, as typically a sour orange is used. But these have the thinner slip-skin, segments and white webbing inside of a member of the tangerine family, not the thick bumpy skin typical of a sour orange. I tried searching on the internet and could find nothing like this fruit. It is not a kumquat or calamondin. Is anyone familiar with what we have here? I would love to make a traditional orange marmalade, even if it may have more of a tangerine flavor.

  • Posted by: Gammy
  • December 28, 2018


BerryBaby December 28, 2018
I think they only ripen if they stay on the tree. In Florida they have many varieties of hybrids so a bit difficult to determine what it is.
Do you have a photo?
The state of Florida has a website with all the varieties of citrus they grow. Maybe that would provide a clue?
Lori T. December 28, 2018
You can't judge the ripeness of citrus fruit by how orange the skin is, especially with tangerines. They tend to turn orange pretty early, but well before they are actually sweet and ready to eat. So the trouble might have been the fruit you tasted wasn't ripe yet. Some varieties don't ripen until January or even February, despite looking supermarket gorgeous. I'd think you ought to leave the fruit on the tree a while longer, and see if it improves. Most citrus can actually hang on the tree for a while without worry. But it won't ripen off the tree, so choosing the moment to pick is very important. You could go ahead and make your marmalade with unripe fruit, though. That's something that happens when a citrus crop gets frost damaged. When I lived in Florida, my landlord's wife did that when it happened to the citrus trees in their garden.
Smaug December 28, 2018
Citrus in general develops sugars in response to cold, so it can be pretty late sometimes. However, I assume the tree's owner knows how it has behaved in past years.
Gammy December 28, 2018
Correct Smaug and Florida has just lost our summer heat! But the owner says the fruit from this tree has been very sour for as long as she can remember. I will sample again in a month as Lori Terwilliger suggests, but history says it will not sweeten much if at all.
Smaug December 28, 2018
I'm still guessing a seedling, but it could possibly be Poncirus (Citrus)Trifoliata, a plant that was once common as a rootstock for citrus and as an ornamental.
Smaug December 28, 2018
Possibly it's a seedling; they tend to lose the selected qualities of cultivated varieties.
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