Rex Union Orange

The Rex Union orange is the result of a cross between a sweet orange and a pomelo. Botanically classified as Citrus x paradisi, the Rex Union is called an orange because of the color of its skin when ripe, but its fragrance and slightly bitter flavor are closer to a grapefruit’s.
Grown in the Rustenburg area, in the lush green Highveld plateau between Pretoria and Botswana, the fruit is called for in many recipes from the start of the last century on. In particular, the Rex Union is the essential ingredient in a traditional marmalade, still produced artisanally and domestically today. Though the basic formula is very simple (water, flesh, rind and sugar), the proportions between ingredients vary and everyone loves to claim they have found the perfect ratio and secret preparation rules, based on the instructions found in dusty home cookbooks and ancient kitchen notes.
The marmalade ritual starts with a hunt for genuine Rex Unions, passing by immense industrial citrus orchards and the many street vendors with heavy sacks of normal oranges, until you reach the place where the Rex Union variety was created at the start of the 20th century, the Lemoenfontein Farm. It was George Wellington Rex who introduced the cultivation of many citrus varieties to South Africa, and it was he who selected this natural hybrid by grafting the first plants right here, where, until recently, the original orchard of around 250 trees was the only place where Rex Unions were still being grown.
South Africa is one of the leading exporters of fresh citrus in the world and the citrus-cultivation industry is the biggest by volume in the national produce market. Across the country, large swathes of land are dedicated to industrial citrus production, including the home of the Rex Union, probably the first place where citrus was grown. However, over the years, South African tastes moved towards sweeter flavors, including in marmalades and jams, which are very popular in the country. This is perhaps why the Rex Union was never produced industrially, instead remaining confined to a single abandoned orchard, left in place in memory of an important historical figure rather than for actual production.