Gwangyang in South Jeolla is where plum blossoms bloom the earliest in Korea. Gwangyang is mild, with Jirisan Mountain and Baegunsan blocking the cold northwesterly wind and, true to its name meaning "light Gwang" (光) and "sunny Yang" (陽), abundant sunshine that keeps the average annual temperature around 14–15 degrees Celsius. With the clean Seomjin River water as well, Gwangyang is considered one of the best places for plum trees to grow.
◇ Gwangyang, where plum blossoms bloom first
In Gwangyang, where the spring scent of plum blossoms fills the air in February–March, the harvest season for green plums arrives in May–June. Thirty percent of the country's green plums are produced in Gwangyang.
According to Gwangyang City, there are currently 3,359 households growing green plums in the area. The cultivation area is 1,200 hectares, and production reaches 5,117 tons. Revenue earned by farms from green plum cultivation alone exceeds 14.4 billion won. Adding in the influx of tourists during the flowering and harvest seasons, green plums have become a key pillar of the Gwangyang regional economy.
Because the flowering period of plum blossoms comes early in Gwangyang, the fruit's "accumulated temperature" (the heat required for crop growth, calculated by summing the daily average temperature over the growing days) is high. That is why Gwangyang green plums have higher sugar content and acidity than those from other regions.
Triggered by a 1970s project to plant fruit trees in rural areas, many plum trees were planted in Gwangyang, South Jeolla, and Hadong, South Gyeongsang. In the 1990s, Hong Ssang-ri, head of Gwangyang Cheongmaesil Farm, was designated a master of traditional foods, and in 2007 Gwangyang green plums were registered as "Geographical Indication No. 36."
Green plums are broadly divided into cheongmaesil and hwangmaesil. They are not different varieties but are distinguished by color depending on the harvest time.
Most plums harvested in late May are green cheongmaesil. Cheongmaesil have firm flesh, so when pickled, they keep a crisp texture. Plums that come out after mid-June ripen yellow and are called hwangmaesil. Hwangmaesil have a strong aroma, making them good for plum wine or concentrated plum extract.
◇ A detox from nature… from aiding digestion to skincare
"The taste is sour and it is nonpoisonous. It dissolves phlegm and stops vomiting, thirst, and dysentery. It reduces fever and relieves alcohol intoxication." Heo Jun described the characteristics of green plums this way in Donguibogam.
Rich in citric acid, green plums help relieve fatigue and boost immunity. They contain organic acids and catechinic acid and are said to help prevent food poisoning. They are also good for stomach upset or indigestion. By removing internal toxins, they are highly effective for skincare.
In 2012, Gwangyang City, through a commissioned study by the Korea Food Research Institute (KFRI), identified that green plums are effective against diabetes and obesity and in improving liver function, and published the related paper in the international journal Food Chemistry. Subsequent studies by multiple research institutions found that green plums suppress influenza viruses and lower blood sugar.