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It can take anywhere from 3 to 6 years to see a bloom realistically. If it has not grown much, then I would chalk it up to its growing conditions. These trees are relatively fast growing, and when they don't you can usually pin that to an issue.

This article will give you more information on what it takes to grow them: https://www.gardeningknowhow.com/edible/fruits/oranges/blood-orange-tree-care.htm

Hello,
Thank you for sending us your gardening question.

Good general growing conditions, soil fertility and water management will in time provide for growth of the stem and branch structure, as well as the foliar crown, flower and fruit development.
In addition to an all-purpose or citrus-specific fertilizer, you may want to consider a root growth stimulation solution with kelp, humic substances, amino acids and micronutrients. A good root system is fundamental for uptake of water and nutrients.

This article will give you some basic information on fertilizing citrus.
https://www.gardeningknowhow.com/edible/fruits/citrus/fertilizing-citrus-trees-best-practices-for-citrus-fertilizing.htm

Please let us know if you have any other gardening questions and happy gardening!

Thanks
Gardening Know How

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Yes, this does appear to be a fertilization issue, as well as possible underwatering. Be sure to keep the soil moist, and feed with a citrus fertilizer. Dolomitic Lime will help maintain proper pH levels in the soil as well. Here is a link that will help: https://www.gardeningknowhow.com/edible/fruits/citrus/fertilizing-citrus-trees-best-practices-for-citrus-fertilizing.htm

If you are sure about the identity of the tree, from a reliable source, then the next thing I would check is if the foliar crown is originating from the grafted scion/stem and not from below the graft. If a sucker has grown up from below the graft and dominated the foliar canopy, then it will not be true to the grafted variety. This is a common issue.

The next considerations are soil fertility and water management. Nutrient deficiencies and water deficit can cause physiological stress and suppress flowering.

You don't state if it's in the ground or in a pot, but in any case a good citrus fertilizer may help:
https://www.downtoearthfertilizer.com/products/blended_fertilizer/citrus-mix-6-3-3/

https://www.gardeningknowhow.com/edible/fruits/oranges/blood-orange-tree-care.htm

Fruit is expected 3 to 5 years after planting. Get going with the fertilizer, those trees are heavy feeders. See the articles below.

https://www.gardeningknowhow.com/edible/fruits/oranges/blood-orange-tree-care.htm

https://www.gardeningknowhow.com/edible/fruits/oranges/no-fruit-on-orange-trees.htm

It most likely is sooty mold and though unsightly, is not harmful in itself. And the fruit is safe to eat. However, it indicates you have an insect infestation. Read below how to manage the insects:
https://www.gardeningknowhow.com/edible/fruits/citrus/sooty-mold-on-citrus-trees.htm