Prunus serrulata 'Ukon'

Prunus serrulata ‘Ukon’ (‘Ukon’ Japanese flowering cherry, synonym: Prunus serrulata f. grandiflora) was described in Japan in 1813. The Japanese called the tree Ukon, after the spice turmeric. But its flowers are not as yellow as the spice. The German doctor, scientist and botanist Philip Franz Von Siebold took the selection with him from his trip to Japan in 1830, making the ‘Ukon’ the first Japanese cherry tree in Europe. The cultivar can reach up to 8 metres in height and has a vase-shaped crown, which can reach a width of up to 5 metres. At a young age, Prunus serrulata ‘Ukon’ absolutely needs formative pruning for a proper branch structure. 

In late April, early May, the ‘Ukon’ selection’s flowers open, at about the same time as the flowers of the Prunus serrulata ‘Kanzan’. The blossoms start out green-yellow and then slowly turn into cream yellow. When the blossoms are almost done blooming, the hearts of the flowers turn pink. Simultaneous with the blossoms, the oval, serrate leaves bud bronze. That makes for a beautiful contrast with the yellow blossoms. The ‘Ukon’ cultivar has spectacular red-violet autumn colours. The bark of the tree is grey-brown and smooth, and the twigs are yellow-green and bare, with the lenticels that are characteristic of Japanese cherry trees. Prunus serrulata ‘Ukon’ bears no fruit. 

The ‘Ukon’ Japanese flowering cherry does not tolerate wet, nutrient-poor or windy environments, but is very strong and healthy otherwise. Plant the tree in a sheltered, sunny place, in nutrient-rich and very permeable soil. Like most trees in the Prunus serrulata family, its wide crown shape makes Prunus serrulata ‘Ukon’ too wide to be used in streets. The tree looks a lot better in (large) gardens, central reservations or other park-like situations.