Oregon is a major producer of blackberries, with over 90% of US-grown frozen blackberries originating here. The state’s unique climate, particularly in the Willamette Valley, provides ideal conditions for growing these fruits. The question of when blackberry season occurs does not have a single answer, as the harvest window stretches across several months and depends entirely on whether the berries are wild or cultivated.
The Timeline: Differentiating Wild and Cultivated Seasons
The Oregon blackberry season is divided into two overlapping periods based on the type of berry. Cultivated varieties are typically ready for harvest in early to mid-July. For instance, the highly prized Marionberry often begins its season around the Fourth of July holiday. This cultivated season generally runs through early August, though some commercially grown types may extend the harvest until September.
The second period is dominated by the wild, invasive Himalayan blackberry (Rubus armeniacus). These berries typically begin ripening in mid-July, peaking in late July and throughout August. While the cultivated crop finishes by the end of summer, wild berries can continue producing fruit well into September, especially in cooler, shaded areas. Weather patterns influence these dates, with warmer summers pushing the harvest window earlier.
Key Blackberry Varieties Grown in Oregon
The most celebrated cultivated blackberry in Oregon is the Marionberry. This trailing variety originated from a cross between the ‘Chehalem’ and ‘Olallie’ blackberries, released in 1956 and named after Marion County. The Marionberry is known for its complex flavor, offering a balance of sweetness and tartness. These medium, conical berries have a glossy, dark color, making them desirable for jams and pies.
The other common type is the Himalayan blackberry, which is technically a noxious weed but is responsible for most roadside foraging. This species is characterized by large, thorny canes and aggressive spread across disturbed areas. The Himalayan berry is larger and sweet, though its flavor is less nuanced than the Marionberry. Other cultivated varieties, such as ‘Oregon Thornless Evergreen,’ offer a later harvest that can stretch into autumn.
Locating and Harvesting Blackberries
To find cultivated berries, the best approach is visiting a U-Pick farm or a local farmer’s market. U-Pick operations provide direct access to delicate varieties like the Marionberry, which do not ship well. It is advisable to check farm websites or call ahead, as the specific start and end dates for U-Pick shift based on weather and picking pressure.
Wild Himalayan blackberries are readily available for free foraging in nearly any undeveloped or disturbed area throughout western Oregon. They can be found along trails, fence lines, and abandoned lots. Foraging requires caution due to the plant’s sharp thorns, so wearing long sleeves and durable pants is recommended. For safety, avoid picking berries directly next to busy roads or in areas where chemical sprays may have been used.