Last year I got a little lazy, and I had a problem with strawberry plants not being pollinated because they blossomed long before last frost. The days were warm, but almost every night had a frost of freeze for about 10 days. I lost a few plants from frost because I forgot to cover a few one night. If a blossom is hit by frost, the center will turn almost black. Frost wont kill a strawberry plant, however, if the blossom or crown freezes or is directly exposed to frost, the plant will not produce blossoms or fruit for that season. My strawberry plants formed blossoms before I got the straw and plastic off of them. There’s about a seven day window for pollination to take place after the blossom has formed. If the flowers are not pollinated during that blossoming period, it will just shrivel up with the petals still on the blossom. A pollinated blossom will drop the blossom petals before shriveling up and forming fruit. I ended up hand-pollinating the blossoms, then covering them up until last frost. I’ve always hand pollinated in years past, and skipping a year really reinforced the importance of hand pollinating.
Pollination’s Relationship to fruit Shape & Size: Almost all Commercial strawberry cultivars produce hermaphrodite flowers, meaning self fertilizing. Hermaphrodite flowers may not be completely self-fertilizing, since the stamens are located such that when they crack open they readily scatter pollen onto the pistils, but not necessarily all, of the pistils. The number of pistils within the flower that are pollinated, has a direct effect upon the size of the fruit and on the shape.
If all pistils are fertilized, a large, perfectly shaped berry will develop. If some of the pistols are not fertilized, then an irregularly shaped berry or nubbins will result, and the fruit will be significantly smaller than a fully pollinated flower. Poor pollination also has a significant effect on the strawberry’s appearance relative to the seeds. This is one of the reason that I usually hand pollinate blossoms and don’t depend on insects to pollinate my strawberry blossoms. Hand pollinating with an artist’s brush can increase your harvest by 30-40%.