New Jersey is one of many states where the highbush blueberry (Vaccinium corymbosum) is a native species. Growing up to 6 feet tall, this blueberry bush thrives across U.S. Department of Agriculture plant hardiness zones 4 through 7. Sometimes referred to as northern highbush to distinguish from southern highbush (Vaccinium corymbosum hybrid), these cold-hardy berries are well-suited to climates in The Garden State, which falls within USDA zones 6 and 7, and resistant to the diseases they may encounter.
The Best Varieties
At least two cultivars planted near one another increases pollination and crop output. For a full range of summer growing, consider planting four plants in two pollination sets. For example, 'Bluetta' and 'Blueray' are mid-June fruiting partners that will bear through early July, while 'Jersey' and 'Lateblue' begin bearing in early July and continue though August.
New Jersey's Salty Soils
Blueberries are one of a handful of plants that enjoy acidic soils, with an optimal pH range between 4.5 and 5.2. New Jersey tends to have alkaline soils, a fact that Rutgers University's New Jersey Agricultural Experiment Station attributes to an excess of sodium from the runoff of winter de-icing salts and exposure to ocean water along the coast.
New Jersey soils range from sand to loam and clay in texture. Sand responds best to amendments, while clay is most stubborn. In general, blueberries in New Jersey enjoy the addition of acidifying organic materials, like pine needles or peat moss. These materials not only increase acidity, but improve aeration and drainage. Soils with pH of 6.5 to 5.2 benefit greatly from the addition, which can bring the pH closer to ideal without chemical treatments.
Apply 4 to 6 inches of organic material like peat moss or compost to the area and till it in to a depth of 6 to 8 inches. After planting the blueberry bush, top dress the area with a 4-inch layer of pine mulch in a 3- to 4-foot circle around each plant.
Large Soil Amendments
For larger pH adjustments, such as those above 6.5, powdered elemental sulfur may be used. Begin by adding 2 pounds of elemental sulfur to a 10-by-10-feet garden, then till it into the first 4 to 6 inches. This should lower the pH by about 1.0 pH point in loamy soils. Retest after one year and re-amend if necessary.
Soils above 8.0 are not recommended for amendment since this is an indication of consistent soluble salt flow into the area, a problem for which there is no easy home remedy. In this case, a raised garden bed is the best option.
Highbush blueberries should be spaced 5 to 7 feet apart in rows 8 to 10 feet apart. The location should have at least six hours of sun exposure per day.
Soils must be moist, but well-drained. Soggy soils contribute to disease and decline, but dry soils can cause a lack of blooms and poor fruit growth. Blueberry plants need 1 to 2 inches of water per week, which equates to approximately 5 to 10 gallons of water per plant. This water is best delivered in a drip system to prevent the blueberries from becoming water-logged.
Fertilization in moderation can help blueberry bushes flourish, but these bushes are also very sensitive to over-fertilization. Do not fertilize newly planted blueberry bushes for at least a month.
It is best to spread out yearly fertilization over the course of several months rather than deliver the entire dose at once. Begin with the first application in April. Spread 1 ounce of a 12-4-8 fertilizer with 2 percent magnesium evenly in a 2-foot circle around the plant's center. Scratch the grains into the soil and water them just enough to moisten the area without creating puddles. Repeat the application in June, August and October each year.
In the second year, provide 2 ounces in a 3-foot circle at each application. In the third year and each year thereafter, provide 3 ounces in a 4-foot circle at each of the four applications.