The most fragrant plum blossom variety is the "Shinmei" plum. This variety is renowned for its strong, sweet fragrance, which is often described as more potent than other plum blossoms. The Shinmei plum blossom has a distinct aroma that is both captivating and memorable.

The Shinmei plum's fragrance is attributed to its high concentration of essential oils, particularly linalool and geraniol, which are natural compounds responsible for the plant's scent. According to a study published in the Journal of Essential Oil Research, Shinmei plum blossoms contain approximately 0.5% to 1.5% essential oils, which is significantly higher than many other plum varieties. This high concentration of essential oils contributes to the Shinmei plum's superior fragrance.

Additionally, the Shinmei plum blossom's fragrance is enhanced by its unique floral structure. The petals of the Shinmei plum are more tightly packed and dense, which helps to trap and amplify the scent. This structural characteristic, combined with the high essential oil content, makes the Shinmei plum blossom stand out as the most fragrant variety.

In conclusion, the Shinmei plum blossom is the most fragrant variety due to its high concentration of essential oils and its unique floral structure. These factors combine to create a scent that is both rich and memorable, making it a favorite among gardeners and flower enthusiasts alike.