Blueberries: A Gardener’s Guide to a Bountiful Harvest
Two types of blueberries grow well in Florida, rabbiteye and southern highbush. However, only the low-chill cultivars of each are adapted to Florida. Generally, rabbiteye blueberries grow well in areas of Florida that have winters as cold as or colder than winters in Central Florida.
Site Requirements for Blueberries
Rrabbiteye and southern highbush blueberries thrive on acidic soils which contain more organic matter than is usually found in Florida soils. Peat moss or pine bark is commonly used to increase soil organic matter in blueberry plantings. Peat moss can be incorporated into the soil at or prior to planting. Pine bark can also be mixed into the soil, or when applied as mulch it will eventually decompose and add to the soil organic matter content. Where blueberry plants are heavily mulched for several years, it’s common to observe many fibrous roots growing in the decomposed litter.
Blueberries require a well-drained soil profile of at least 18 inches in depth. If blueberry roots are exposed to water-saturated soil for many days, damage from Phytophthora root rot may become severe. Generally, blueberries will grow well where azaleas, camellias, and other “acid-loving” plants are proven performers.
Set plants in a sunny area (minimum 4-5 hours of full sun per day) away from tree roots, except pines. In addition, set them at least 20 feet away from any building foundation. Southern highbush plants tend to be less vigorous and smaller than rabbiteyes. Plant size can be controlled to some degree by pruning. However, severe pruning will reduce yields the following spring. Allow at least a 7’ x 7’ area for rabbiteyes and a 4’ x 4’ area for southern highbush. Plants may be set 3 feet apart (southern highbush) or 5 feet apart (rabbiteye) for a hedgerow effect.
Blueberries – Planting & Establishment
The best time to plant blueberries is from mid-December to mid-February. It is best to use plants about 1.5 to 2 feet tall with well-developed root systems. The root balls of potted plants should be broken up slightly. The plants should be set at the same height as when they were growing in the nursery. If blueberries are planted on raised beds, flatten the bed in the vicinity of the plants. Set the plant in a slight depression so that irrigation and rain water will not flow away from the plant.
Pine bark mulch aids in the establishment of young blueberry plants. You can provide a good substrate for surface feeder roots by doing one of the following. Lay pine bark 3 inches deep and extend it out about 2 feet from the plants in all directions. Or lay a strip of pine bark about 4 feet wide extending down the row. Mulch also moderates soil temperatures, aids in weed control, provides protection from mechanical injury, and adds organic matter to the soil. Weed control is extremely important for young plant establishment because blueberries are shallow-rooted plants. This makes them compete poorly with weeds for water and nutrients.
Cultivars
Aside from site selection, choosing proper blueberry cultivars may be the most important decision a backyard blueberry grower can make. Most blueberry cultivars grown in Florida require cross-pollination from another cultivar of the same type. In this case, southern highbush with southern highbush and rabbiteye with rabbiteye. Another requirement for good fruit set is that pollen vectors (usually bees) are present and working the flowers during bloom. With good pollination, berry yields of 2-5 pounds per plant may be expected by the third or fourth year. Some of the major blueberry cultivars commonly grown in Florida are:
Common Southern Highbush Cultivars
Common Rabbiteye Cultivars
Fertilization
We recommend Espoma’s Berry-Tone when fertilizing your blueberry plants. Spread fertilizer evenly over a circle 2 feet in diameter with the plant in the center. Repeat this procedure in April, June, August, and October. Use as directed for best results!
Irrigation for Your Blueberries
Mature blueberry plants need about 40 inches of water annually. Most of this water is provided by rain. Water requirements for blueberry plants are low during the winter. Normally, the combination of rainfall and water stored in soil should limit the need for irrigation between December and March. The most critical period for irrigation of blueberry plants in Florida is from early fruit set until the end of harvest. The frequency of irrigation depends on the weather, soil type, and type of blueberry (rabbiteye or southern highbush). Established rabbiteye blueberries in gardens will require irrigation only during prolonged dry periods. They are as drought tolerant as evergreen azaleas. Southern highbush blueberries planted on very sandy soils may require three or more irrigations per week during dry periods.
Weed Control
Weeds compete with blueberry plants for water, nutrients, and sunlight. You can help control weeds and add acid to the soil in the plants’ root zones by maintaining several inches of acid-forming mulch. Pine bark, pine straw, or oak leaves can be used. Woven nursery fabric ground cover or plastic ground cover may be used as synthetic mulches. However, these will not add to the soil organic matter. Be aware that these ground covers may reduce the availability of nutrients from surface-applied fertilizers, and they may complicate irrigation and fertilizer practices
How to Prune Blueberry Bushes
- Clean out old, dead wood
- Keep three best 1-year-old canes.
- Locate the oldest canes and prune out one of every six existing canes; cut as close to the ground as possible
A mature blueberry bush should have 10 to 15 canes each of 1-, 2-, 3-, 4-, and 5-year old canes.
