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Nearly all caneberry cultivars are self-fruitful, and therefore self-pollination or pollination by the same cultivar will result in fruit development. Commercial growers should consider placing one or two hives of honeybees per acre grouped into units of five or ten hives per location.

The time from flowering to fruit harvest can vary significantly for both blackberries and raspberries. Keep records of peak bloom and harvest each year to help manage your harvest (see Table 8 for an example for blackberries). Over time you should be able to estimate when harvest will start, peak, and end. Simply record the dates that you observe the stages of development from flowering through fruiting on three or more fruit. We suggest flagging the fruit with colored tape and returning to the same fruit each week to observe and record changes. Flagging three or more fruit ensures that you will have fruit by the end of the season to observe, as fruit can be lost from accidental picking or other mishaps. A step-by-step protocol for monitoring flower to fruit development is available at NC Cooperative Extension’s Team Rubus blog. Print out a copy of Table 9 to use as a record for each cultivar.

Table 8. Days from flowering to fruit development of erect thornless floricane-fruiting blackberries in Clarksville, Arkansas.
Osage Apache Natchez Navaho Ouachita
50% Bloom 2 May 8 May 29 April 7 May 6 May
Peak Fruiting 26 June 6 July 17 June 1 July 29 June
Number of Days 55 59 49 55 54
(Source: Hort Sci 2013. 48:909-912. Hort Sci. 2005 40: 259-260.

Table 9. Monitoring flower to fruit development in your field. (Enter the dates that you observe each stage for three flowers of each cultivar.)
Stage Flower 1 Flower 2 Flower 3 Comments
Full bloom
Petal fall
Shiny black
Dull black


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As the fruit ripens, it grows in size and weight. Color changes from green to red to black. Blackberries take 35 to 45 days to mature once they are pollinated.


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Flavor and sugars increase as the fruit grows, and the fruit will soften and loosen from the receptacle when ripe. About 85 percent of the fruit size is gained in the last days of maturation. Development at this time depends on adequate supplies of carbohydrates and water; any limitation will adversely affect fruit size.

Raspberry fruit also grows in size and weight. Color changes from green to light red to red. Raspberries mature approximately 30 days after they are pollinated. Ripe fruit separates from the plant, leaving the torus (or core) attached to the plant.


Extension Specialist (Small Fruits)
Horticultural Science
University of Arkansas
University of Tennessee

Find more information at the following NC State Extension websites:

Publication date: Nov. 2, 2015

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