Plums can be picked slightly before they are ripe and will then reach perfect ripeness in a warm room. Refrigeration slows the process but does not stop it.
The best way of preserving plums is to dry them naturally, as with prune varieties and also the Bokhara plum (Prunus bokhariensis), used in the cuisines of C. Asia and the northern fringe of the Indian sub-continent.
Plums are also candied to make ‘sugar-plums’, the most notable kind being Portuguese Elvas plums. Jams and jellies made from sour, wild varieties such as damsons are better than ordinary plum jam.