Blueberries: An alternative crop for Florida

J.G. Williamson 
Horticultural Sciences Department
IFAS, University of Florida 
Gainesville, FL 32611-0690 

Introduction

             Two types of blueberries are grown in Florida: 1) southern highbush (Vaccinium corymbosum hybrid) are grown for the commercial early-season shipping market; and rabbiteye (V. ashei Reade) are grown for u-pick, roadside and local consumption.

 Southern highbush blueberries: Florida is the major producer of early-season southern highbush blueberries during the period from April 1 through May15. Florida's early-season fruit are the first blueberries to ripen in North America. Prices are generally strong for fresh blueberries during this period. Much interest  in commercial blueberry production has resulted in many new plantings of southern highbush blueberry throughout the Florida peninsula, primarily from Gainesville south to Highlands County because of the threat of freezes in more northern locations. Southern highbush blueberries are extremely susceptible to late winter and early spring freezes because of their early bloom period. In most cases, very sophisticated overhead irrigation systems would be necessary to protect flowers from freezes in north and north-west Florida. Southern highbush are also difficult to grow from the standpoint of proper soil, irrigation, and disease management. The costs and potential risks for growing southern highbush in areas subject to late winter or early spring frosts, such as much of the Suwannee River Valley, are high. For these reasons, few southern highbush plantings have been established in northwest Florida or in the Suwannee River Valley.

Rabbiteye blueberries: Rabbiteye blueberries have been grown throughout the Southeastern United States, including north and northwest Florida for many years. Generally, rabbiteye blueberries are easier to grow and better adapted to north and north-west Florida than are southern highbush. Rabbiteye blueberries bloom later than southern highbush and are less susceptible to late winter and early spring freezes. Rabbiteye blueberries are also more drought tolerant than southern highbush and better adapted low organic matter soils. However, all blueberries require well drained, acidic, soils and benefit from soil organic matter and mulch. Rabbiteye blueberries ripen later than southern highbush and receive significantly lower prices in the commercial shipping market. However, they are ideal for u-pick and local markets where fruit prices do not fluctuate greatly. Results of a statewide survey in 2000, indicated that rabbiteye blueberry acreage had declined over the past 10 years while southern highbush acreage grown specifically for the commercial shipping market had increased. One conclusion from the study was that rabbiteye blueberries grown for u-pick and local sales are currently underutilized in Florida.         

Variety Descriptions 

            Brief descriptions of blueberry varieties found in Florida are given below. Although most of these cultivars may be found in the trade, they are not all  recommended for use in Florida. All blueberries grown in Florida benefit from cross pollination of 2 or more cultivars. Adequate cross pollination does not occur between rabbiteye and southern highbush types. Adequate cross-pollination may or may not occur between two varieties of a given type ( for example two rabbiteye varieties) depending on respective bloom periods and other factors.  

Rabbiteye Varieties  

            'Aliceblue' is an early-ripening variety with a chilling requirement between 350 and 400 chill units. It is upright and vigorous with high quality fruit of good size, color and firmness. The fruit can be harvested mechanically for the fresh market. 'Aliceblue' is no longer recommended for Florida because of poor flower bud initiation due to leaf diseases and erratic fruit set, probably due in part to partial cross-incompatibility with 'Beckyblue'.  

            'Beckyblue' is an early-ripening variety released by the University of Florida in 1977. Its chilling requirement is about 350 chill units. Early flowering makes 'Beckyblue' more susceptible to spring freezes than most other rabbiteye varieties. Fruit have good color, size and firmness. Leaves are susceptible to several leaf spot diseases which result in reduced flower bud initiation. Yields have been low in peninsular Florida because of low flower bud numbers and poor fruit set. Although early season for a rabbiteye, it is not recommended in Florida because of low productivity.  

            'Bonita' is an early-ripening variety released by the University of Florida in 1985. Its chilling requirement is about 350 chill units. Plants are moderately vigorous and develop dense bushes with numerous canes. Fruit have good color, size and firmness. It is moderately susceptible to Phytophthora root rot. 'Bonita's yields have been low in peninsular Florida because of low flower bud initiation due to leaf diseases and poor fruit set. Although its early season for a rabbiteye, it is not recommended in Florida because of low productivity.  

            'Climax' is an early-ripening variety released by the University of Georgia in 1976. It has a concentrated harvest season with high quality fruit that are well-adapted to mechanical harvesting. It has fruited more reliably in Florida than 'Beckyblue' or 'Bonita' but its flower buds are highly susceptible to infestation by the blueberry gall midge. Midge infestations may also interfere with normal leafing during the spring growth flush. Climax is recommended for north Florida where an early-season rabbiteye cultivar is desired.  

            ‘Premier’ is an early ripening variety released from North Carolina State University. Bushes are vigorous and productive. Fruit have excellent size, color and flavor. Bushes are highly susceptible to blueberry gall midge. Premier is suggested for trial in north Florida where blueberry gall midge is not present.   

            'Chaucer' is a high-yielding, early-season variety released for U-pick purposes by the University of Florida in 1985. Its chilling requirement is between 350 and 400 chill units. It is not recommended for mechanical harvest or long distance shipping because of a poor picking scar.  

            'Brightwell' is a mid-season variety released by the University of Georgia in 1983. Plants are vigorous, upright, and are excellent producers. Brightwell is probably the best and most productive rabbiteye for north Florida. Recommended for u-pick and local consumption.  

            'Tifblue' is a mid to late season variety released by the University of Georgia. Plants are vigorous and upright in growth. Fruit are medium-sized, light blue, and firm with good flavor, but tart until fully ripe. Fruit may crack during rainy weather which can be a problem in Florida since harvest is during the rainy season. It has not been as productive in Florida as 'Brightwell' or 'Powderblue'.  

            'Powderblue' is similar to 'Tifblue' in season, appearance and harvesting characteristics. It can be used to pollinate 'Tifblue' and 'Brightwell'. Powderblue has been one of the most reliable mid-season rabbiteye cultivars in north Florida. Recommended for u-pick and local consumption.  

Southern Highbush Varieties - note that southern highbush are more susceptible to late winter and early spring freezes than rabbiteye varieties. While southern highbush may be the blueberries of choice for commercial shipping in peninsular Florida, there is little justification for growing them in north or north-west Florida for u-pick or local sales. Production of southern highbush in north and north-west Florida for commercial shipping is theoretically possible; but growers in north and north-west Florida would probably be at a competitive disadvantage compared to growers in peninsular Florida. Nevertheless, southern highbush varieties are widely available in the trade in Florida; therefore, some of the more popular varieties are described below. 

            'Sharpblue' is an early-season variety released by the University of Florida in 1976. It is the industry standard for its early season, and it is the most widely planted southern highbush variety in Florida. The fruit are large with good flavor, but fruit for the fresh market must be hand harvested. Overhead irrigation is suggested because of its early bloom period. Sharpblue is moderately susceptible to Phytophthora root rot, stem blight, and several leaf spot diseases. In Florida, 'Sharpblue' ripens most of its crop before the late May drop in berry prices. Not recommended for north or north-west Florida because of susceptibility to spring freezes.  

            'Misty' is a very early variety with good fruit size and quality, and a dry picking scar. It is currently the major pollinizer for 'Sharpblue'. 'Misty' plants tend to flower heavily and leaf poorly in the spring. This combination results in a heavy berry set with insufficient leaves to support the crop; this results in very late fruit ripening and renders the plants highly susceptible to blueberry stem blight. For the first two years after planting, flowers and young fruit should be removed from 'Misty' plants before spring growth begins. The growth regulator Dormex is generally needed for adequate leafing of Misty plants of bearing age. Suggested for trial in north Florida if southern highbush are desired, and if used in conjunction with Dormex. 

            ‘Star’ is a 1998 release from the University of Florida that is adapted to peninsular Florida from Alachua County, north. It blooms about 10 days after Sharpblue but has a short bloom to ripe period with a concentrated harvest so that fruit harvest is as early or earlier than Sharpblue. Berries are large and firm with excellent picking scars. Suggested for trial in north Florida if southern highbush are desired. 

            ‘Millenium’ is a recent release from the University of Florida. Early bloom and harvest. Fruit have good firmness and flavor and variable picking scars. The plant leafs well as it begins flowering. Suggested for trial in north Florida if southern highbush are desired.  

            ‘Windsor’ is a recent release from the University of Florida. Berry color is similar to Star and Sharpblue. Firmness is good with a good to excellent picking scars. Plants appear to be somewhat susceptible to Phytophthora root rot. Suggested for trial in north Florida if southern highbush are desired. 

Note that because of their early bloom period, southern highbush grown in north Florida will require protection from late winter and early spring frosts and freezes most years.