Plums are technically classified as stone fruits, or drupes, belonging to the genus Prunus. This botanical group also includes familiar fruits such as peaches, cherries, and apricots. Plum season is centered around the warmest months of the year in the Northern Hemisphere, marking a welcome influx of fresh fruit during the summer.
The Primary Plum Harvest Window
The commercial plum season in North America generally extends from late May or early June through the end of September. This long stretch of availability is not due to a single type of plum but rather a carefully managed sequence of different cultivars that ripen throughout the summer months. The vast majority of the United States’ plum supply originates from major growing regions like California, with some additional production coming from states such as Oregon.
The peak window for many commercial operations typically runs from mid-July through late August. Growers track key metrics like sugar levels, measured in Brix, and fruit firmness to determine the exact moment to begin harvesting each specific block of trees.
Seasonal Differences Among Plum Varieties
The plum family is largely divided into two main categories, each with a distinct ripening schedule that contributes to the extended season. Japanese plums, scientifically known as Prunus salicina, are the earliest to mature, typically becoming available from late June through July. These plums are often larger, rounder, and known for their juicy texture and characteristic sweet-tart flavor, making them ideal for fresh eating. Popular early varieties like the Santa Rosa plum are often the first to appear on the market in mid-summer.
In contrast, European plums, designated as Prunus domestica, are later-season fruit, with their main harvest starting in August and continuing through September. These plums are generally smaller, oval, and have a denser, firmer flesh that is often freestone, meaning the pit separates easily from the pulp. Cultivars like the Italian Prune and Damson plums fall into this group and are particularly well-suited for drying into prunes, baking, or preserving.
Identifying Peak Ripeness
When selecting plums during their season, consumers should rely on a combination of visual, tactile, and olfactory indicators to judge peak ripeness. A ripe plum displays a deep, even color across its entire surface, whether it is purple, red, yellow, or green, and should not have any patches of green, which indicate it was picked too early. Many varieties will also have a natural, powdery white coating called a “bloom,” which is a sign of freshness.
To check for texture, gently apply pressure to the fruit, ideally near the end opposite the stem, where it should yield slightly. The plum should feel slightly soft and resilient, but never mushy or excessively yielding. A perfectly ripe plum will also emit a distinctly sweet and fruity scent, as an unripe plum will have little to no discernible aroma. If a plum is still slightly firm upon purchase, it can be left at room temperature for a few days to soften; however, the sugar content will not increase significantly once the fruit has been separated from the tree.