The Ume tree grows 15 to 30 feet high (5 to 10 metres.) It has jagged-edged leaves up to 4 1/2 inches (11 1/2 cm) long and 3 inches (7 1/2 cm) wide.
Blooms up to 1 1/4 inches (3 cm) wide appear on the tree very early in the spring before the leaves do, as early as February sometimes. One variety of Ume has white blossoms, another has red blossoms. There are also some pink-blossomed varieties.
Ume plums are quite small, only up to 1 1/2 inches (3 3/4 cm) wide, with fuzzy green skin ripening to greenish yellow. When allowed to fully ripen, they turn bright yellow with an orangey-red blush on one side.
When unripe, they contain the same toxin as do bitter almonds.
Inside there is 1 small pit to which the flesh clings (e.g. clingstone.)
Ume plums can’t be eaten raw because they are too tart and bitter.
Most are made into umeboshi. When made into umeboshi, the flesh become plum coloured and the flavour is more like a plum, though the purple colour actually comes from shiso leaves used in making the umeboshi.
There are more than 300 cultivated varieties of Ume in Japan.
Ume is native to China. Arrived in Japan sometime in the mid to late 700s.