There are five main types of blueberries grown in the United States: northern highbush, southern highbush, rabbiteye, lowbush, and half-high. The northern highbush is most common type grown worldwide and in the Pacific Northwest.
This publication briefly describes each type of blueberry. Tables 1 and 2 list cultivars that are suitable for the Pacific Northwest.
Northern highbush blueberries (Vaccinium corymbosum) are native to much of the eastern and northeastern United States, from the Appalachian Mountains to the Atlantic Ocean. The plants grow 5 to 9 feet tall. One named selection from the wild, ‘Rubel’, was introduced in the early 1920s. Many commercial northern highbush cultivars have been developed through traditional breeding programs. Northern highbush cultivars are listed in Table 1.
Southern highbush blueberries are complex hybrids of V. corymbosum and a native, evergreen Florida species (V. darrowii). The plants grow about 6 to 8 feet tall. In mild production regions, southern highbush blueberries can be grown in an evergreen system, in which the plants retain old leaves through the winter to advance the spring fruit crop.
This type was developed to allow blueberry production in low-chill areas (regions with mild winters, such as Florida and California). A dormant blueberry plant requires a certain amount of chilling (between approximately 32°F and 45°F) to break bud and flower normally. Southern highbush blueberries have a much lower chilling requirement (200 to 300 hours) than northern highbush blueberries (more than 800 hours).
Southern highbush blueberries will grow in the Pacific Northwest but have low yields. Bushes bloom in late winter, and flowers are frequently damaged by frost. We do not recommend southern highbush blueberry cultivars for the Pacific Northwest. Some hybrid cultivars, such as ‘Legacy’ and ‘Ozarkblue’, can be grown successfully west of the Cascades; however, cold damage to flower buds has been observed in these cultivars when temperatures drop below approximately 0°F to 5°F.
Rabbiteye blueberries (V. virgatum syn. V. ashei) are native to the southeastern United States. The plants grow from 6 to 10 feet tall. Rabbiteye cultivars were developed in regions with long, hot summers, and they behave differently in the Pacific Northwest than in their home environments. In this region, the plants tend to be smaller, and the fruit ripens very late in summer and fall. In some cool summer environments, such as the Pacific Coast and northwest Washington, there often is not enough heat to fully ripen the fruit.
Rabbiteye blueberries are more sensitive to winter cold than northern highbush blueberries. Although we have not seen much cold damage on rabbiteyes grown in Oregon’s Willamette Valley, cold damage to flower buds and late-season growth has been observed when temperatures drop below approximately 0°F to 5°F. We do not recommend this type of blueberry for production east of the Cascades or in northern Washington.
Though newer cultivars have fruit quality similar to that of highbush types, many older rabbiteye cultivars have darker blue fruit with more noticeable seeds, thicker skins, and noticeable grit or stone cells (as found in pears). Rabbiteye cultivars are listed in Table 1.
Lowbush blueberries (V. angustifolium) are native from Minnesota to Virginia and to the northeastern United States and the Maritime Provinces of Canada. The plants are low-growing shrubs that spread by underground stems; they seldom grow taller than 1.5 feet. A few cultivars, such as ‘Blomidon’, ‘Burgundy’, and ‘Brunswick’, have been named, but the lowbush blueberry industry depends on managing wild stands made up of hundreds or thousands of clones per acre.
Plant more than one cultivar for good fruit production. In general, lowbush types need little pruning, but cut plants back to the ground every 2 to 3 years if they get too shrubby.
Half-high blueberries are the result of crosses between northern highbush and lowbush blueberries. These cultivars will tolerate -35°F to -45°F. The plants grow from 3 to 4 feet tall, and most of the fruiting area is protected below the snow line. Half-high blueberries are suitable for commercial production where other types of blueberry are not hardy. They are also used as attractive landscape plants and are suited to container production. In the landscape, they do not need to be pruned as severely or as regularly as high-bush types. Half-high cultivars are listed in Table 2.
Although highbush blueberry cultivars are generally self-fertile, cross-pollination by another cultivar produces larger berries. Choose a pollenizer within the same blueberry type to ensure good berry size and yield. All northern highbush blueberries are compatible with each other for cross-pollination. Rabbiteye and lowbush blueberries are not self-fertile. Rabbiteyes require a different rabbiteye cultivar for successful pollination, and lowbush blueberries can be pollinated by either another lowbush or a highbush cultivar for successful pollination and fruit production.
Although most commercial blueberry production in Oregon is west of the Cascades, northern highbush blueberries are successfully grown in eastern Washington, some areas of Idaho, and eastern Oregon. In these regions, growers must contend with shorter growing seasons and colder winter temperatures, and selection of cold-hardy cultivars and protection from spring frost damage are especially important.
Harvest dates vary tremendously among cultivars, but cultivars bloom within about a week of one another. Thus, selecting a mid- to late-season cultivar does not necessarily ensure a late bloom date and reduced susceptibility to spring frosts.
Of the early-season cultivars, ‘Duke’ and ‘Spartan’ tend to bloom later than average. Late-season cultivars ‘Elliott’, ‘Jersey’, and ‘Ozarkblue’ tend to bloom later than early and midseason cultivars. ‘Legacy’ has a particularly long bloom period.
Short growing seasons in high-elevation and high-latitude sites present challenges for cultivars that ripen after ‘Liberty’ (particularly ‘Elliott’ and ‘Aurora’); these cultivars may not ripen reliably before fall frosts.
In eastern Washington, particularly cold sites in northeastern Oregon, and Idaho, plant only the most cold-hardy cultivars. Avoid ‘Legacy’ and all rabbiteye cultivars. The half-high cultivars listed in Table 2 are recommended for particularly cold production regions where snow can also protect plants. These cultivars also work well in containers and in home gardens as ornamentals.
The cultivars in Table 1 are all northern highbush blueberries unless otherwise labeled. Table 2 lists half-high blueberry cultivars. Not all of the listed cultivars are available in nurseries; however, these are included in the tables because plants are long lived, and established plantings of older cultivars exist.
Fruiting season varies by production region. In Oregon, the blueberry fruiting season extends from late June through September, depending on type and cultivar (Figure 1). In Washington, production does not begin until early to mid-July, and the season finishes earlier than in Oregon. The fruit on each cultivar ripens over period of 2 to 5 weeks.
Descriptions of berry size and yield are primarily based on results of trials by the USDA-ARS/OSU cooperative breeding program at the OSU North Willamette Research and Extension Center in Aurora, Oregon. If a cultivar has not been tested at this site, yield and berry descriptions are based on grower experience throughout the Pacific Northwest.
Pruning severity affects berry size. Evaluations of berry size were done on well-pruned plants.
When a berry is picked from the fruit stem (pedicel), a scar is left on the base of the berry. A cultivar that has a small or “dry” scar will ship and store better than one that has a large or “wet” scar.
A commercial value score is provided to help commercial growers select appropriate cultivars for fresh and processed markets:
1 = Appropriate for most commercial operations
2 = May have commercial value but:
(a) not enough is known about its performance
(b) may meet a specific requirement (e.g., unique color or very early harvest) but has a negative trait (e.g., low yield or poor shipping quality)
3 = Unlikely to have good commercial value
Cultivars that are well suited to small farms, local sales, U-pick farms, and home gardens are noted as such.
Find out as much about it as you can, such as its growth habit, hardiness, fruit characteristics, disease susceptibility, and machine harvestability (important for commercial growers).
Remember: If you purchase a cultivar that is not on these lists, it probably hasn’t been extensively tested in this region. It’s best to try a few plants first and see how well they grow and how you like the fruit.
Highbush Blueberry Production (PNW 215). Oregon State University Extension. (under revision in 2014)
Growing Blueberries in Your Home Garden (EC 1304). Oregon State University Extension.
A Grower’s Guide to Pruning Highbush Blueberries (DVD 2). Oregon State University Extension. Available as a DVD (for purchase) or as a free online video in English or Spanish.