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Prunus salicina 

Mariposa Plum is a Japanese blood plum with dark red flesh and large fruit if thinned. The flavour is excellent, the skin glossy red and it has a egg shaped fruit.

Remember that most plum trees need to be planted near other types of plum trees so that they can pollinate each other and produce fruit. Mariposa plums are pollinated by  Satsuma and Santa Rosa Japanese plum trees.