Agriculture Research Stations have released many new "half-high" blueberries, making it possible for us to produce reliable crops in Zone 3-4, where most of the standard highbush blueberry cultivars (Bluecrop, Berkeley, Earliblue) sustain frequent extensive winter injury. Seven of these new half-highs were bred using the Ashworth blueberry, which originated here at St. Lawrence Nurseries. The shorter varieties, like Northblue, are readily covered by snowfall, which affords them additional winter protection.
The soil for good blueberry culture should be modified toward high acidity (pH 4.0-5.0). A heavy annual application of pine needle mulch will accomplish this, or, if more radical acidification is needed, plain sulfur will do the trick. Take time to test the pH of your soil; blueberry plants will be sickly if the soil is not acid enough. Since you will have to provide water and bird protection to the crop, plant a small bed or patch rather than a long row. A good continuous water supply is a must (drip irrigation or overhead), especially during fruit set, enlargement and ripening. Insufficient water results in small, poor quality berries. Screening for birds is also necessary. A tightly enclosed plastic or wire mesh should be used during the entire ripening period if you expect to get fruit.
Northblue and Northcountry 4 feet, while Bluegold, Chippewa, Friendship, Patriot, Polaris and Superior require 4-5 feet between plants. Northland should be allowed 5-6 feet between plants. Spacing between rows should be 6 to 8 ft.
How long before they fruit?
Blueberries will bear some fruit the second year. They should be producing a good crop 4 years from planting if their cultural requirements are fulfilled.