Pruning is an essential part of blueberry production. It is used to promote postharvest growth
of new foliage and fruiting wood, balance vegetative and reproductive growth, reduce disease
and insect pressure, assist in mechanical harvesting efficiency, promote new cane growth and
plant longevity, and help establish new plantings.
Postharvest Hedging
Postharvest hedging or topping is typically done shortly after fruit harvesting is finished, usually
in late May or early June. Delaying hedging until mid-to-late summer may negatively impact
floral bud differentiation and yield. Many growers use mechanical hedgers or sickle bars
mounted on tractors to reduce plant height to around 40–48 inches, while also trimming the
sides of the plant so they do not spread too far into the row middles (Figure 1). While many
growers hedge straight across the top of the plant, some growers prefer a “rooftop” cut angled
45–55 degrees up to a point in the center of the plant canopy. Hedging promotes growth of the
plant canopy and new fruiting wood (Figure 2), and is essential to vigorous, healthy growth
throughout the summer (and through fall and winter for evergreen production). Hedging also
allows greater sunlight penetration into the canopy, which may increase the number of flower
buds. While most southern highbush cultivars respond well to this pruning, it should be noted
that ‘Chickadee’ does not. Several growers have reported that ‘Chickadee’ can struggle to
achieve significant regrowth following hedging, especially after the plant is around 2 years old.
These growers have adopted the practice of lightly tipping ‘Chickadee’ following harvest instead
of the typical hedging.
In addition to promoting vegetative growth, hedging can help reduce disease pressure by
removing fungal disease pathogens from the field. It also opens up the plant canopy to allow
for better air flow (promoting faster foliage drying and therefore less fungal disease) and better
coverage when spraying fungicides and insecticides. Hedging can also remove damaging insects
from the plant’s top growth, including wax scale and blueberry bud mites. Because hedging can
create an entry point for disease pathogens such as Botryosphaeria (stem blight), it is important
to spray a fungicide, such as captan, immediately after hedging to help minimize the
opportunity for plant infection.
Figure 1. Blueberry field following mechanical hedging
Credits: D. Phillips, UF/IFAS
Figure 2. Regrowth following summer hedging
Credit: D. Phillips, UF/IFAS
New Plant Establishment
Growers may consider removing around ⅓ to ½ of the top of young blueberry plants when they
are planted in the field if they have become long, leggy, and rootbound in their containers. This
will help balance the top of the plant with the root system until root growth can support a
larger plant top. It was previously common practice to remove flower buds from young plants
in the first year after planting to encourage foliage and canopy growth. However, on certain
vigorous cultivars in the evergreen system some growers have been harvesting young blueberry
plants within 12 to 18 months after planting. Therefore, removing buds in the first year is not
recommended in every situation.
Many growers interested in machine harvesting have begun to place cardboard cartons or
plastic sleeves over new plantings during the first two years to train the plant to have a
narrower crown, which can help reduce ground loss during harvesting (Figures 3 and 4). The
cartons may also protect young stems from herbicide damage, and (in certain cultivars) reduce
the need for pruning of suckers emerging from the bottom of the plant. However, once the
cartons are removed, continued pruning at the base of the plant is needed to maintain a
narrow crown.
Figure 3. Cardboard cartons on young blueberry plants.
Credits: J. Williamson, UF/IFAS
Figure 4. 'Farthing' plant previously trained to a narrow crown with cartons.
Credits: J. Williamson, UF/IFAS
Cane-Renewal Pruning
After a blueberry plant is around 4 to 5 years old, cane-renewal pruning should be performed
each year to stimulate the growth of new canes and open the plant canopy for better airflow
and sunlight penetration. This can help encourage plant vigor, lengthen the productive life of
the plant, and reduce fruit load if needed to promote earlier ripening and larger fruit. Around ¼
of the oldest canes should be removed each year by cutting them back to the plant crown or to
a strong lateral point. Dead, weak, crossing, or low-spreading branches can also be removed at
this time. Cane-renewal pruning is typically done during December or January in Florida, when
plants in the deciduous system are dormant, although it can also be performed at the same
time as summer hedging.
Rejuvenation Pruning
If blueberry plants have not been pruned for several years and are unproductive, it may be
possible to rejuvenate the plants through aggressive pruning, depending on the cultivar and
overall plant health. With this method, all of the plant’s canes are hedged back to 1–2 feet,
either in early summer or during winter when deciduous plants are dormant. This will
significantly reduce the yield on these plants for the next one or two seasons. If growers have
this situation and are evaluating this type of pruning, they should consider using it on only a
portion of their field in a year to maintain some level of production during this process.
Dr. Jeff Williamson, Professor, UF/IFAS
Doug Phillips, Blueberry Extension Coordinator, UF/IFAS
