Answer: The two major possibilities that come to mind are damage from a late frost or poor pollination of the flowers. If you had a late frost, that could have zapped all the developing berries. Lack of or incomplete pollination can be caused by excessive rain at blossom time, leaving the berries covered with a frost blanket during the daytime and thus excluding the bees from pollinating, poorly timed use of a chemical toxic to bees, or simply a lack of bee activity in the area. There's not much you can do about excessive rainfall. Be sure to remove any frost blankets to allow bees to visit the flowers, and avoid use of toxic sprays. Planting flowers that attract bees can help bring them to your yard.
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