When should you harvest plums?
As plums approach maturity, the fruit develop their characteristic color. The fruit of blue or purple varieties (‘Stanley,’ ‘Damson’ and ‘Mount Royal’) change from green to greenish-blue, then to dark blue or purple. The ripened fruit color of other varieties varies from yellow to red. Color, however, should not be the sole basis for harvesting plums. As they ripen, plums begin to soften, especially at the tip end. They also develop their characteristic flavor.