Wednesday, November 23, 2011

Growing Rabbiteye Blueberries

Rabbiteye blueberries (Vaccinium ashei), native to the Southeastern United States, are popular with backyard gardeners in that part of the country. The earliest varieties were bred from native plants found in Georgia and Florida. The berries, large and sweet, are produced from late May to late July. The shrubs thrive in the heat, and have no significant insect or disease problems. Maintenance is minimal. Most varieties mature in about 10 years, but may produce small crops in as few as 3 years. Some grow as tall as 12 feet and 10 feet across.

I strongly recommend consulting with your Cooperative Extension Service office for choosing varieties that have proven successful for your area. Rabbiteye blueberries are generally hardy in USDA climate zones 6 to 9. Careful variety selection is a more important consideration having to do with flowering time and avoiding frost damage.

Popular varieties include the following:

'Tifblue' is one of the most widely planted. It was an early introduction from the University of Georgia Experiment Station in Tifton, GA. Fruits are large and ripen late in the season. The bush is large and vigorous. It's one of the more cold-hardy varieties.

'Woodard' is a large, light blue rabbiteye blueberry that ripens early. This and Tifblue are the old, tried and true standards. You can't go wrong with either.

'Climax' ripens early and in a short period of time. Quality and size is good. It's perfect for commercial operations harvesting with machines, or for backyard fruit growers who need to get it done and take a vacation.

'Brightwell' produces heavy yields of medium-sized fruit. It ripens early to mid-season. Include this one in your garden for blueberries between the early and late crops.

'Briteblue' is a medium-size shrub that produces large, light blue berries. Crops vary from year to year with moderate to heavy crops. It ripens early to mid-season.

Rabbiteye blueberries require well-drained, moist, acid soil with a pH of 4.0 to 5.0. Soil should be high in organic matter. Soil moisture can be maintained with irrigation or heavy mulch. Raised beds should be constructed in low-lying sites where too much water accumulates.

Cross-pollination is essential for good yields. Two or three varieties should be included in every planting. Bees do the work.

Before planting, take a soil sample to your nearest Cooperative Extension Service office for analysis. Follow the recommendations.

Begin preparing the site by spraying weeds with glyphosate herbicide. When weeds have died, till the area, wait for dormant weed seeds to germinate, then spray the area again with glyphosate. Peat, compost or pulverized pine bark should be worked into the area.

Select two-year-old bare-root or container-grown plants. When planting, do not allow the roots to dry. Bare-root plants should be kept covered and moist until the moment they are planted. Water container-grown plants in their pots, and allow to drain well before planting.

After removing the pots, the roots of container-grown plants may need to be teased out from the root ball. If tightly compacted, the root ball may be sliced a bit around the sides and bottom to encourage better root penetration into the soil.

Blueberry rows should be at least 10 feet apart. Closer spacing will make it difficult to move between the rows when the shrubs mature. Plant spacing is a matter of preference. They may be planted as close as 3 feet apart in rows to form hedges. Most backyard growers prefer spacing 6 feet apart.

Set the plants 1 inch deeper in the planting hole than they grew in the containers or nursery row. Some growers recommend pruning the tops of the bushes back by one-half at planting time, but the benefit is debatable.

As the bushes grow taller, they also produce sprouts from the base. The bushes spread as the sprouts mature. Berries are borne on the previous year's growth. In order for the plant to have abundant crops, new wood must be produced annually. Therefore, fertilization is important. Care must be taken regarding the type of fertilizer and the timing of applications.

Plants such as blueberries, azaleas and camellias which thrive in acidic soils are very sensitive to nitrogen. Therefore nitrate-based fertilizers should not be used unless in a very slow-release form. Ammonium sulfate or special azalea/camellia fertilizers are safer.

Newly planted rabbiteye blueberries should not be fertilized when planting. Fertilizer may be applied the second growing season. Applications should be small and frequent, with no more than 1 ounce of ammonium sulfate applied during the second growing season. In future years, the application may be increased by 1 ounce per year, but never more than 1/2 pound per plant. Fertilizer should be distributed around the plant, not at the base of it.

Mulch is very beneficial, especially for young blueberry plants. It helps to conserve moisture, control weeds and reduce soil temperature. Pine straw, pine bark, leaves, grass clippings and compost are frequently used. Apply mulch 4 inches deep extending from the base at least 2 feet, and further out as the plant matures.
Even with mulch, weeds can be troublesome. Small plantings may be hand-weeded. Larger plantings may require weed control with a selective herbicide. Consult with your Cooperative Extension Service for appropriate recommendations.

Irrigation is essential for young plants, and beneficial for older ones, especially during harvest. Weekly irrigation is better than daily, promoting deeper root penetration into the soil. Rabbiteye blueberries are by nature shallow-rooted. Provide 3 to 4 gallons per week for young plants. Fully mature blueberry shrubs may require up to 30 gallons per week, depending upon rainfall.

Rabbiteye blueberries need little pruning. Lower limbs can be removed to keep the fruit off the ground. Plant height may be reduced to keep fruit within reach. Dead limbs should be removed. Pruning is best done between the time of harvest and flowering the following spring.

Depending upon the location, weather and blueberry variety, flowering may begin as early as February, making frost damage a very real possibility. Again, consulting with your Cooperative Extension Service for appropriate varieties for your area can be helpful.

Blueberry harvest spans 4 to 6 weeks, perhaps longer if varieties with different harvest times are selected. A normal season can extend from late May to late July. Blueberries should not be harvested until they are ripe. They won't ripen off the bush. A mature shrub can produce up to 15 pounds of fruit.

Rabbiteye blueberries have few pests; birds are the peskiest. The few diseases that afflict them are usually associated with environmental stresses such as drought or overwatering. They can usually be controlled by maintaining a proper environment, and pruning out affected parts.

In addition to the fruit, rabbiteye blueberries can be ornamental. A profusion of white to pale pink, bell-shaped flowers are beautiful in spring. Fall turns the foliage to scarlet.

Considering the fruit, landscape value, and ease of cultivation, it's no wonder that rabbiteye blueberries are so popular throughout the south.

John J Marshall
goGardenNow.com
John also blogs at goGardenNow.blogspot.com.

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