Florida’s winter season is shorter and milder than most, with periodic warm spells throughout. Most fruit cultivars that lose their leaves at the end of the growing season have high chilling requirements and do not grow well in Florida. To produce the best fruit yield and quality, most deciduous fruit cultivars need to be exposed to temperatures below 45ºF during the winter, which is more than they are likely to experience in Florida. If a plant does not receive enough chilling, it will not have a good flower or leaf growth in the spring. Growth can be weak and erratic. However, some deciduous fruits have low-chill cultivars that have been developed by plant breeders at the University of Florida and elsewhere. These cultivars were developed specifically for regions with mild winter temperatures such as in the north and central parts of Florida.
One of the most important decisions a blueberry grower can make is choosing the right cultivars. Most blueberry cultivars grown in Florida are self-unfruitful and require cross-pollination from another cultivar of the same type. For a good fruit set, it is also necessary that pollen vectors (usually bees) are present and active during the flowers’ bloom. If the plants are pollinated well, you can expect to get 2-5 pounds of berries per plant by the third or fourth year. The following are descriptions of some of the major blueberry cultivars commonly grown in Florida.
Southern Highbush Cultivars. The earliest blueberries to ripen in North America are grown in peninsular Florida. Cultivars of this type are usually seen as more challenging to grow when compared to rabbiteye types. Southern highbush cultivars are not suited for the extreme north and northwest Florida because their early flowering makes them quite susceptible to late winter/early spring freezes. In addition, southern highbush blueberries have less tolerance for soil requirements and are generally more vulnerable to diseases such as Phytophthora root rot. In central or south Florida, southern highbush cultivars are usually preferred over rabbiteyes.
Emerald was released by the University of Florida in 1999. It is widely planted in north and central Florida. It appears to be adapted from Gainesville to Sebring. Emerald is a vigorous, spreading bush with high yield potential that ripens early and produces large, high-quality berries. “Emerald” flowers open at the same time, and it produces a lot of leaves even after mild winters in Gainesville. The plant is very strong and can produce a lot of fruit when grown in the right conditions. ‘Emerald’ normally reaches full bloom in Gainesville around February 15, thus flowers and fruit would be damaged by freezes in February and March. In Gainesville, the first Emerald harvest occurs a few days earlier than for Sharpblue and Star. The fruit of ‘Emerald’ is normally ripe between April 15 and May 10 in Gainesville.
The University of Florida breeding program released ‘Jewel’ in 1999. It has a moderately low chilling requirement, very early ripening, and high berry quality. ‘Jewel’ seems to be best suited to the region of Florida from Gainesville to Sebring. The Jewel typically flowers a week before the Star and ripens at approximately the same time. On average, ‘Jewel’ is harvested in Gainesville on April 12th, with harvest finishing around May 10th. Jewel leaves well in the spring, despite producing a large number of flower buds. It has a lot of energy, so it’s able to produce a lot of good berries. The quality of its berries is excellent but they tend to be tart until fully ripe. The apple’s berry size is medium to large, its firmness is good to excellent, and its stem scars are dry and considered to be excellent. Jewel is not resistant to Phytophthora root rot and is very susceptible to rust leaf spot disease, which means it may lose its leaves early in the fall if fungicide sprays are not used.
The University of Florida released “Star” in 1995. ‘Star’ does not grow vigorously, but it has survived well in the wild. Star requires more chilling to produce fruit than Emerald or Jewel and does best in north Florida and southeast Georgia. ‘Star’ does not perform well in areas with little winter chilling, such as few flowers and weak vegetative growth. The average date for the ‘Star’ variety of camellia to reach 50% bloom in Alachua County is February 23. The first half of the crop is expected to be ripe by April 26. ‘Star’ leafs out well in Gainesville and southeastern Georgia. The plant “Star” has a very short amount of time between when it blooms and when it is ripe. The harvest period is only about three weeks long.
In 2001, the Windsor variety was released from the University of Florida breeding program. It is vigorous, with stout stems and a semi-spreading growth habit. Based on its growth patterns, ‘Windsor’ appears to be best suited for north-central Florida, although it has been known to thrive in southern areas such as Hardee County. The average bloom date for 50% of the flowers in Alachua County is February 21, which is usually a few days after the ‘Emerald’ flower and about three days before the ‘Star’ flower. Windsor grows a lot of leaves when it starts to flower, which lets it hold a big crop. In Alachua County, fruit ripens anywhere from early April to mid-April. 50% of the berries are ripe by April 24. ‘Windsor’ berries are very large. The average weight of berries from the first half of the harvest is about 2.4 grams on young vigorous plants. The berries of this plant are a similar color to those of ‘Star’. It has good firmness and excellent flavor. Picking Windsor apples can be difficult because of the deep scar left on the fruit, but this generally isn’t a problem for people who grow them at home.
The “Springhigh” cultivar is especially hardy and does very well even in difficult growing conditions. The plant is apparently of hybrid origin This plant is apparently a hybrid that is best suited to north-central and central Florida. The “Springhigh” cultivar of apple ripens earlier than the standard mid-season cultivars by 5–10 days. The berries are of a good size and have a pleasurable taste. The berries of ‘Springhigh’ have a lower level of waxy bloom on their surfaces, compared to most other cultivars. This gives them a darker color. The scars on the berries are not very deep and tend to tear the skin around the picking scar during harvest. The firmness of the fruit sometimes presents problems during commercial packing and shipping, but should not be an issue for home gardeners. The berries of the ‘Springhigh’ plant are very attractive to flower thrips, which are often abundant during the weeks when the berries are ripening. If you don’t keep the thrips population down when ‘Springhigh’ is ripening, the berries will get soft and won’t last as long after you’ve picked them.
The “Sweetcrisp” plant is strong and can survive well in fields. It also has a growth habit that causes it to spread out. This flower blooms around the same time as the ‘Jewel’ variety, which is later than the ‘Emerald’ and earlier than the ‘Star’ or ‘Windsor’. The fruit ripens at approximately the same time as the ‘Jewel’ and ‘Emerald’. The berry tastes sweet with a crisp crunch when you first bite it. It is very firm and has exceptional postharvest life. The berries on this plant are smaller than similar varieties, and the size can vary depending on the width of the twig that the flower is growing on. Gainesville’s flower bud numbers and berry yields are lower than average, and it seems to thrive better in northern Florida and southern Georgia. This cultivar is especially promising because of its excellent berry quality and the fact that it can be stored post-harvest.
The ‘Farthing’ plant is known for its vigorous growth and dense, compact canopy. The leaves are typically healthy and don’t have many leaf spot diseases. berries are large and firm and have a good picking scar, but because of low surface wax content, they tend to be dark in color. Too many flower buds may form if ‘Farthing’ is not pruned while dormant. The ‘Farthing’ flower blooms later than most Florida cultivars, but before the ‘Star’ or ‘Windsor’ flowers. The berries on ‘Farthing’ ripen at the same time as ‘Star’, but it produces more berries than ‘Star’. The ‘Farthing’ cultivar has done well in north-central Florida, but since it is new, it is not clear how well it will do in other areas.
Rabbiteye cultivars. Cultivars of rabbiteye blueberries are easier to grow than those of southern highbush blueberries. They can live in dry conditions and are not easily killed by Phytophthora root rot. The flowers bloom later in the spring, so they are less likely to be damaged by late winter or early spring freezes. They require less organic matter and less mulching, and they are generally more disease resistant. The fruit of the rabbiteye blueberry bush has a slightly tougher skin and slightly larger seeds than the fruit of the southern highbush blueberry bush. The fruit from rabbiteye cultivars typically lasts longer than fruit from southern highbush cultivars. Rabbiteyes require cross-pollination from another rabbiteye cultivar. The rabbiteye blueberry harvest season can last from May to July, depending on the cultivar. Rabbiteyes are most effective in northern Florida, near Ocala.
There are three early-season rabbiteye cultivars that are widely grown in Florida. They are ‘Beckyblue’, ‘Bonita’, and ‘Climax’. These types of cultivars generally ripen later in the season around May or early June in the Gainesville area. Early-season rabbiteyes have not been as productive in Florida as the mid- to late-season cultivars. Although they don’t provide a large yield, rabbiteye blueberries are helpful in prolonging the rabbiteye berry picking season. To ensure optimal pollination, grow ‘Climax’ alongside either ‘Beckyblue’ or ‘Bonita’. The newer early-season rabbiteye cultivar ‘Austin’ appears to grow well in the same areas as ‘Climax’ and should cross-pollinate with other early-season rabbiteye cultivars.
The mid- to late-season rabbiteye cultivars are more productive than the early-season rabbiteye cultivars and are therefore better suited for home gardeners. The garlic varieties ‘Brightwell’, ‘Powderblue’, ‘Tifblue’, and ‘Woodard’ have done very well in north Florida and in the panhandle. These varieties of rabbiteye plants bloom later in the season, and the flowers and young fruit are less likely to be damaged by late winter freezes.
PRUNING BLUEBERRIES STEP BY STEP
Before cutting any branches on your blueberry bush, there are a few things you should keep in mind. Pruning can introduce diseases by transmitting them through dirty shears or by making messy cuts. It is important to sanitize your shears with rubbing alcohol before starting to pick berries so that the berries will be safe to eat. Use sharp shears that cut through the cane without tearing it.
Pruning is best done on a day when the weather is dry. Wait until the blueberry plant has had a chance to start healing itself after pruning before exposing it to rainfall, which can cause diseases from raindrops coming from the ground.
Identifying Fruit Buds and Vegetative Buds
Leaves are an important part of a blueberry bush, and without them, the bush can sometimes look like a pile of twigs just randomly stuck in the ground. Why not take a few minutes to discover what you have in front of you! Examine the small branches closely to find two different types of buds that are starting to form. You should see larger buds that are shaped like teardrops, as well as smaller buds that are shaped like small triangles. These smaller buds may look like they have thorns.
The flowers that start out as teardrop-shaped buds turn into blueberries after they are pollinated. The triangular buds will become the leaves, and the following year, the fruitwood will grow lateral to it. The number of teardrop-shaped buds on a branch can help you decide whether to keep it on your blueberry plant.
Remove the oldest canes which have just a few teardrop buds. The canes which are three to five years old and have the most buds will produce the most fruit. Be sure to leave those.
The First Cut
ALL gardeners should follow a few basic guidelines for pruning, regardless of the type of blueberry bush they’re growing. Every year, cut out wood that is over 6 years old, wood that is crossed, and wood that is diseased. These are dead branches and are easy to identify because they are dark brown or black and have no new growth.
Grizzled wood is often hard and unyielding. Sometimes, it even has moss growing on it. You should cut away the older canes on the plant so that it can put its energy into the new growth.
When removing dead branches, cut at an angle that is level with the branch, or flat at the ground level. Pruning cuts should be done at a 45-degree angle.
New vs. 6-Year-Old Growth
Every year, blueberry canes produce berries on the same canes. Even though they only produce berries on new wood, a single cane will keep putting out new growth on the same cane for a long time. Once a blueberry bush reaches 3-5 years old, it will produce the most berries. In general, blueberry bushes produce the most berries between years 8-10.
An ideal number of canes for a mature bush is 15-25, with only 3-5 new canes each year. Cut back any excess new canes in your blueberry bushes, so that you only have 3-5 new canes per year.
Pruning for Shape and Airflow
Remove the central stems from a mature blueberry bush to allow air to reach the center of the plant. Pests are less likely to infest bushes that have sufficient airflow. Additionally, get rid of small canes that grow close to the ground, are less than 1-2 feet tall, or protrude into an aisle or walkway. The branches are likely to become bent throughout the season, or the fruit will pull the branch towards the ground, inviting disease.
You should cut off any weak shoots, even if they have fruit buds on them. Prune old side growth in the form of twigs, the goal is to have blueberry fruits that don’t touch fruits from other branches.