Mulberries (species of the genus Morus) are fast-growing, deciduous trees prized for their abundant and sweet fruit. Understanding the specific window when mulberries ripen is essential for a successful harvest, as the season is often rapid and intense. This knowledge allows for preparation, ensuring the brief period of peak sweetness is not missed.
General Fruiting Season by Climate
The primary fruiting season for mulberries generally spans late spring through mid-summer, creating a harvest window from roughly May to July in temperate regions. The exact timing is highly dependent on local climate conditions and accumulated warmth. Trees in warmer, southern climates often begin ripening earlier, sometimes yielding their first crops as early as April.
Trees located in cooler, northern areas typically do not see ripe fruit until later in the summer, often closer to July. The initiation of the reproductive cycle requires the tree to accumulate a specific amount of winter chill, often around 400 hours below 45 degrees Fahrenheit, to trigger spring blooming. Once flowering occurs in early to mid-spring, the subsequent fruit set progresses quickly as temperatures rise, leading to the early summer harvest.
Timing Differences Among Species
The duration and timing of the fruiting season are significantly influenced by the specific Morus species being cultivated. The three most common species—white, red, and black—have distinct schedules that affect when their berries ripen.
Species Timing
Morus alba, the White Mulberry, often begins its fruiting period earlier than the others. Morus rubra, the native Red Mulberry, typically follows in the mid-season, producing its reddish or black fruits after the initial white varieties have begun. The Black Mulberry, Morus nigra, generally ripens the latest, often extending the season into late summer.
Everbearing Varieties
While most mulberries yield a heavy, concentrated harvest once per year, some cultivars are bred to fruit sporadically. These everbearing types, which often have Morus alba parentage, can produce smaller, continuous crops throughout the entire warm season, sometimes yielding a second crop in the fall.
Identifying Ripe Mulberries and Harvesting
Once the fruiting window arrives, knowing how to identify a perfectly ripe mulberry is essential for maximizing flavor. A ripe berry will show a deep, saturated color—dark purple or black for red and black varieties, or a full, non-green white or golden color for white varieties. The fruit should feel soft to the touch but not mushy, indicating a high sugar content.
The most reliable indicator of ripeness is the ease of detachment from the tree; a mature berry will release from its stem with only a gentle tug. If force is required to remove the fruit, it should be left on the branch to ripen further.
Due to the small size and quantity of the berries, hand-picking is inefficient for a full harvest. The most effective method for collecting mulberries is to lay a clean tarp or sheet on the ground beneath the tree’s canopy. The branches can then be gently but firmly shaken, causing the ripe fruit to fall directly onto the sheet. Because mulberries are extremely delicate and have a short shelf life, they should be used immediately or preserved by freezing or drying soon after harvesting.