Dekopon (Citrus reticulata ‘Shiranui’) is a seedless mandarin variety, that is a cross between the Ponkan or Chinese honey orange (Citrus poonensis) and the Kiyomi (Citrus unshiu × sinensis).
Dekopon produces large fruit ranging from 8 – 10 cm in diameter, with a round shape and a distinct bulge on the top that is sometimes referred to as a top knot. The bumpy skin is bright orange and approximately 4.8 mm thick, and beneath is a thin layer of pith, which protects the delicate hesperidium (sectioned) pith.
Dekopon is a portmanteau made up of deko which means bump or uneven and pon, in reference to the ponkan mandarin. Initially, this unusually shaped fruit didn’t attract much interest, however, the sweet flavour of this fruit eventually won the public over. There is a growing interest in Dekopon outside Japan.
Dekopon is a species of citrus native to Japan where it is known for its sweet, almost seedless fresh and unique conical shape. The large fruit has a bright orange colour that is harvested in winter. Dekopon is considered to be one of the best-tasting citrus fruits and is highly prized in Japan and it is given as a gift or used in high-end culinary dishes.
Dekopon was developed in 1972 by the Agricultural Research Organisation, Nagasaki Prefecture. The goal was to produce an easy-to-peel, sweet citrus with no seeds. Initially, the fruit was not registered due to the unattractive bump on the top and the sour taste of the fruit immediately after harvest. Seedlings were transported to Shiranui-cho, Uto-gun, Kumamoto Prefecture, where they grew in a test garden. Shingo Nagame, director of the experimental garden ate a fruit that had been harvested and left out and found the fruit had developed a sweet taste.
The generic name for Dekopon is ‘Shiranuhi’, is named after the former town Shiranuhi (不知火町), which was located in Uto District, Kumamoto Prefecture and is now Uki City.
Dekopon is a trademarked name owned by the Kumamoto Fruit Agricultural Cooperative Association. In Hiroshima, the Dekopon is marketed as Kiyopon, and unlike Dekopon, this name doesn’t appear to be trademarked.
In South Korea, the Dekopon is known as ‘hallabong’, named after Hallasan Mountain on the island of Jeju, where the fruit is primarily grown.
Dekopon is one of the most popular fruits in Japan and worldwide interest is rapidly increasing. The flavour of Dekopon is described as a cross between an orange and a mandarin. A thin membrane covers the segments, which are firm, juicy and sweet with a slightly acidic taste.
Brix refers to the sugar content in citrus fruits. While all Dekopon are ‘Shiranuhi’, not all Shiranuhi are Dekopon. For the fruit to be called Dekopon, it must reach a minimum of 13 Brix but can be as high as 18 with 1.0% citric acid levels. This is in contrast to oranges with an average Brix level of 10 and 6 for limes.
In Japan, Dekopon is usually grown in a large greenhouse to ensure a constant temperature. Ripe fruit can weigh between 250 grams and are harvested during the winter months.
The main production areas are Kumamoto, Ehime, and Wakayama Prefectures.
Outside Japan, Dekopon is sold under the trademarked name Sumo Citrus as a licensed and controlled brand. Citrus farmer Brad Stark Jr. imported a budwood branch into the United States in 1998. The importation of citrus into the United States is mostly prohibited to protect farmers as well as prevent introducing pests and diseases into the country. These cuttings were grown in quarantine for several years.
In the meantime, Brad Stark Jr. went bankrupt and Brad sold the rights to the Griffith family, who owned Suntreat. The development of Dekopon was kept under wraps until they could properly cultivate them and release a branded version, eventually settling for Sumo, presumably due to the fruit’s resemblance to a sumo wrestler. Dekopon fruit must be a certain size to be considered a Sumo citrus.
Due to the difficulty growing Dekopon, it took until 2011 before the fruit was released to the public.
Pacific Fresh brought the Dekopon to Australia in 2011 where it is grown commercially at a small level. The ripe fruit is available between June and August in Woolworths stores. Dekopon is also grown in Brazil, which produces 300g tonnes of fruit per year.
It appears that Dekopon trees are primarily sold to commercial farmers and are not available to the public. Some people have attempted to grow trees from seeds found in the flesh of the fruit, however, the Dekopon has been bred to not produce seedy fruit, so finding seeds is often not possible.
Almost all citrus trees are grafted, to guarantee the tree will be a clone of the parent plant. Citrus trees grown from seed won’t necessarily be the same stock as the parent. However, the Dekopon is polyembryonic, which means the seed produces more than one seedling which is different to that of the parent. If you do choose to grow Dekopon from seed, bear in mind it can take up to 15 years for the tree to produce fruit.
Dekopon is a versatile fruit that can be enjoyed in several ways.
- Fresh: Simply peel the fruit and enjoy the juicy and sweet flesh.
- Juice: Squeeze the fruit to make a sweet juice that can be enjoyed on its own or in cocktails.
- Liqueurs: Carefully remove the zest from the fruit, without the bitter white pith underneath. Combine the zest with vodka in a large glass jar and let it sit in a cool, dark place for 7-10 days or until the vodka has taken on the Dekopon flavour. Strain the vodka mixture to remove the zest. Make a simple syrup by combining 1 litre of water with 1 kg of sugar, and heat over medium heat until dissolved. Once it has cooled, combine the simple syrup with the vodka mixture to make a Dekopon ‘limoncello’.
- Desserts and cakes: Dekopon rind, juice and segments can be added to desserts, cakes and icing for a sweet, refreshing taste.
- Salads: Finely grated zest can be added to salad dressings and fresh fruit segments go well in salads.
- Marinades: Blend Dekopon fruit with soy sauce, vinegar, honey, and garlic for a sweet and savoury baste for red meat, poultry, or seafood.
- Sushi: Dekopon can be used as a substitute for traditional citrus as a topping for sushi rolls. The sweet and slightly acidic flavour compliments the salty and savoury flavours of the rice and other ingredients. The fruit is typically sliced thinly and arranged on top of the sushi roll.
How to store Dekopon?
Store Dekopon the same way as other citrus varieties.
- Room temperature: Dekopon will last approximately a week at room temperature. Store away from direct sunlight and heat sources.
- Cooler temperature: For longer storage, store them in the refrigerator, where they will last for several weeks.
- Avoid ethylene: Do not store citrus near fruits and vegetables that produce ethylene gas, such as apples, bananas, and tomatoes, as this can cause the fruit to ripen and deteriorate more quickly.
Dekopon simple syrup
This syrup can sweeten and add a citrus flavour to cocktails, teas, lemonades, and other beverages. It can also be drizzled
Dekopon citrus salad
Dekopon panna cotta
Julia is a writer and landscape consultant from Wollongong with a love of horticulture. She had been an avid gardener for over 30 years, collects rare variegated plants and is a home orchardist. Julia is passionate about learning and sharing her knowledge of plant propagation and plant toxicology. Whether it’s giving advice on landscape projects or sharing tips on growing, Julia enjoys helping people make their gardens flourish.