The Berkeley Blueberry (Vaccinium corymbosum ‘Berkeley’) is a classic Northern Highbush cultivar highly valued by both commercial growers and home gardeners. This deciduous shrub is a popular choice for its dependable, heavy annual yield of exceptionally large fruit. It is a vigorous grower that combines high production with an attractive plant habit, making it one of the most widely planted blueberry varieties in temperate regions.
Defining Characteristics of the Fruit and Bush
The fruit of the ‘Berkeley’ cultivar is notable for its substantial, often very large size and slightly flattened shape. Berries ripen in mid to late season, typically from late July through August. They are prized for their light, powder-blue color caused by a heavy natural bloom on the skin. The fruit possesses a mild, sweet flavor profile and a firm texture, allowing for excellent handling, extended storage, and suitability for both freezing and fresh consumption.
The bush develops into a moderately spreading, multi-stemmed shrub, typically reaching a mature height and spread of four to six feet. Beyond fruit production, the plant offers ornamental appeal, featuring delicate white, bell-shaped flowers in the spring. In autumn, the glossy green foliage transitions to striking shades of scarlet. The cultivar is considered cold-hardy, performing well across USDA hardiness zones 5 through 8.
Essential Growing Requirements
Successful cultivation of the Berkeley Blueberry hinges on providing a highly specific soil environment. Like all highbush blueberries, it requires an acidic soil pH, ideally maintained between 4.5 and 5.5. Soil testing is recommended before planting. If the native soil is not sufficiently acidic, amendments like elemental sulfur or peat moss should be incorporated to lower the pH.
The plant requires a site that receives full sun, meaning a minimum of six to eight hours of direct sunlight daily, to ensure the highest possible fruit set and yield. Because blueberries have a shallow, fibrous root system, the soil must be well-drained yet consistently moist, as the plant cannot tolerate standing water or prolonged drought. Applying a thick layer of organic mulch, such as pine needles or wood chips, helps to regulate soil temperature, conserve moisture, and suppress weeds.
As a Northern Highbush variety, ‘Berkeley’ requires a significant period of winter dormancy to set fruit buds for the following season. This requirement is quantified by chilling hours—the cumulative hours between 32°F and 45°F needed for the plant to break dormancy. For ‘Berkeley,’ this requirement is generally between 800 and 1,100 chilling hours, making it best suited for regions with reliably cold winters. While the cultivar is self-pollinating, cross-pollination is recommended to maximize production. Planting a second, different highbush variety nearby, such as ‘Bluecrop’ or ‘Jersey,’ will significantly increase the size and quantity of the harvest.
History and Development
The ‘Berkeley’ cultivar traces its origins to the extensive highbush blueberry breeding programs of the mid-20th century, which aimed to develop varieties suitable for widespread commercial use. It was developed at the University of California, Berkeley, and officially introduced to the public in 1949. The parentage is recorded as a cross between ‘Stanley’ and a hybrid of ‘Jersey’ and ‘Pioneer.’
The breeding goals for ‘Berkeley’ included achieving exceptional fruit size, superior plant vigor, and a high-yielding habit. Its introduction was part of a wave of new varieties released during the late 1940s and early 1950s that transformed blueberry cultivation by offering larger, firmer berries. The lasting success of ‘Berkeley’ is a testament to this breeding work.