As weird as they seem, blood oranges are a class of common orange, Citrus X sinensis. Their fruit may resemble common sweet oranges externally, or may be blushed with red. Internally, the flesh exhibits red streaks or blotches, or is more uniformly garnet red. Cool autumn weather enhances red fruit color. ‘Tarocco’ may not develop any red color locally.
‘Sanguinelli’ is likely the most popular cultivar here. It produces relatively small fruits with peachy external blush. Their trees are relatively large and upright. ‘Moro’ produces larger unblushed fruits with darker and more uniformly red flesh. Their trees are relatively broad and low. While ‘Sanguinelli’ is more of a juicing orange, ‘Morro’ is more a dessert orange.
Blood oranges are quite popular in Europe, particularly within the Mediterranean region. Their flavor is more tart and berry-like than that of sweet oranges which are popular here. Blood orange trees are quite happy with the climates and soils here. They prefer regular irrigation while young, but become less demanding as they mature. Dwarf trees are most proportionate to gardens.
Tony Tomeo 
They are beautiful. If they are available here in the U.S. they are usually quite expensive. We’ve really been enjoying the small Mandarins this year. We have a large 5 lb bag in our crisper fridge drawer right now. We have two to three every day with meals. We haven’t any colds yet this year and we think part of it is these delicious sources of Vitamin C. Your photo looks like a work of art.
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I can not imagine why blood oranges are not more popular than they are. Those that I find in stores, including those in the picture, are not as good as those from home gardens. I would guess that they are imported from far away. When I grew citrus trees in the 1990s, we grew and sold blood orange trees, so I know that they are out there somewhere.
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I wish my area was warm enough to grow citrus trees. We are iced in now…waiting for a big melt…hopefully, but it is so cold.
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I am glad that we do not get such weather here. Gardening would be very different. It will be in the low 70s today. It is even warmer in Southern California.
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Sounds wonderful!
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It is for now, but could prompt some species to bloom prematurely. Premature bloom can be damaged as wintry weather resumes.
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That’s true here too, so often the peach trees will bloom too early and then most of the season’s harvest is lost when frost descends.
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