In recent years, the U.S. blueberry industry — including the Mid-South portion — has benefited from favorable health-related information.

“Blueberry growing is definitely changing and progressing,” says John Braswell, Mississippi State University Extension professor. “It’s become a food in big demand. People are eating a lot of blueberries, sales have gone up and volume has gone up across the United States.”

In Mississippi, there are some 3,000 acres of blueberries with around 125 growers. In a good year, the state produces about 8 million pounds of blueberries. A good yield is about 10,000 pounds per acre.

Most of the state’s blueberry acreage — about 80 percent — is in the southeast quarter of Mississippi. “Fifteen percent is in the southwest quarter and about 5 percent in north Mississippi, above I-20. But the vast majority is below I-20 on the eastern side of the state.”

Asked if there’s a reason for the concentration, Braswell says blueberries are actually native to the Southeast United States and grow in pine forests.

“There are a lot of wild blueberries growing in our pine forests. The rabbiteye blueberry that we grow commercially is one of our native species. Of course, it’s been bred up through breeding programs to produce good, quality fruit. But it’s adapted to that growing environment — and the southeast part of Mississippi is largely in piney woods.”

As you travel north, the soil pH and types change and the forests change to mainly hardwoods and cedars. It’s harder to grow blueberries there.

Braswell is stationed at the South Mississippi Experiment Station in Poplarville — a USDA experiment station — that has been doing work with small fruits since the early 1970s.

Much of the early Mississippi blueberry production began around the station. “There was no blueberry acreage prior to this station beginning work on the crop. Researchers here selected varieties, developed some cultural practices and then the industry sprang up from this area. That’s another reason why there’s a concentration of blueberry acreage in the southeastern part of Mississippi.”

The blueberry industry in the northern United States began in the early 1900s. “Michigan and New Jersey are big blueberry-producing states. Three types of blueberries are grown in the United States. Highbush blueberry varieties are grown in the Northeast and Northwest. Lowbush varieties are grown in Maine. Rabbiteye varieties are grown in the Southeast.”

The rabbiteye blueberry varieties were developed for production in the South. The research began in Georgia in the 1950s. Mississippi researchers began working with them in the 1970s.

Are there lines, cultivars or varieties that have branched off?

“It’s kind of like row-crop varieties. The blueberries that were being grown in the 1950s aren’t around anymore. In fact, you wouldn’t be able to find the plants for most of them.

“There’s an active breeding program here at the Poplarville Experiment Station, another in Georgia, Florida and North Carolina.”

New varieties are released “pretty regularly.” Most of the blueberry varieties being planted this year have been released within the last decade. As with rice varieties, “the new varieties are more vigorous, more productive with disease resistance and corrections to past problems.”

Establishing a planting

To establish a blueberry planting, select a site and lay out the rows. “Ideally, the rows run north to south. Till the rows and place 3 to 4 inches of pine bark on top. The bark is then tilled into the soil. Pull the soil/bark mixture up into a bed, 8 to 10 inches high.”

The blueberry plants are then planted 5 feet apart down the row. Drip irrigation lines are placed and mulch is placed on top of the soil.

“Mulching increases the organic matter in the soil and keeps the soil loose, moist and cool in a uniform manner throughout the year. The plants really respond well to that. The mulch also help control weeds.”

How long is the planting process?

“Ideally, you’d start a year in advance with weed control, eliminating perennial weeds before planting. Growers will spend a summer getting the soil ready and then plant that winter.”

Two-year-old plants are used to plant. “These plants spent their first year in a propagation bed and the second year in a pot in a nursery. At the end of the second year they are placed in the ground.”

By the third growing season, growers should get a good yield. By the fifth year, they should be getting maximum yield from the plants.

There are mechanical harvesters developed for blueberries. Braswell says those have improved over the last decade.

But the majority of the fresh fruit is hand-picked. The processed grade fruit is machine-harvested. So, there’s still a lot of hand labor.

Once picked, the berries are taken to a processing, or grading, facility. They go over a grading line where the fruit is sorted. The good fruit is packed in pint containers and put in a flat which holds 12 pints — about 10 pounds. Those berries are then shipped all over the country.

Agronomics

Currently, all blueberries being planted are irrigated.

“I don’t know of any blueberries being planted without irrigation. Many blueberry fields are fertilized through the irrigation systems. That’s true of most of the new acreage planted over the last five or six years.

“It’s much more efficient to inject fertilizer through the irrigation system than to apply granular fertilizer: you can monitor it closely, use a small amount every week and provide just what the plant needs. And making adjustments is very easy.”

The nitrogen source growers use is either urea or ammonium sulfate. Blueberries do not respond well to ammonium nitrate and it is damaging to the roots.

“On mature blueberry plants, we recommend applying about 30 pounds of actual nitrogen in a complete fertilizer in the spring. In mid-summer, right after harvest, growers make another application of nitrogen.”

Braswell also says “P and K are important. We take soil samples every two or three years to see what’s needed. P and K concentrations build up, so you need to monitor them. If they’re building up, growers will adjust how much they provide.”

Now, growers are taking leaf samples in addition to soil samples. “They study those and make adjustments for maximum production and nutrition.”

Early varieties begin producing berries in mid-May.

“Most varieties mature their fruit over a three-week period. Early varieties begin in mid-May and are complete by mid-June. Later maturing varieties continue into July.”

As harvest is completed, growers begin pruning and applying a late application of fertilizer.

“Usually we just hedge them a bit, shape them up, and trim the perimeter of the plant to encourage new growth. That new growth is where the fruit will be the next year. We also cut out old wood as it begins to slow down and become less productive.”

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