Each pollinated blueberry blossom produces one blueberry.
And like the fruits and seeds of most plants, the size and quality of that blueberry will be dependent upon how well the blossom was pollinated.
For many plants, the best pollination is achieved when pollen from the male parts of one plant is transferred to the female parts of a different plant of the same species, rather than just within the same blossom.
This is called cross-pollination.
Most blueberry varieties are self-fertile.
This means that as long as blueberry pollination occurs within a flower (or among flowers of the same variety), that flower will set fruit and produce a blueberry.
But blueberries happen to be among the set of plants that benefit from cross-pollination.
For most blueberry varieties, blueberry pollination will be more complete when a blossom is cross-pollinated with another variety.
This means that more seeds will be formed as a result of the blueberry pollination, resulting in a larger berry.
When you’re selecting blueberry varieties for your garden, trying to assure that you’re picking varieties that will cross-pollinate each other can be a bit ‘headachy.’
There are so many different varieties of blueberries within each species (rabbiteye, highbush, etc.) to choose from. And there’s no ‘master chart’ of blueberry pollination – that I’m aware of, anyway – that lists every possible variety of every species and shows what other varieties are compatible as cross-pollinators.
So how do you know which varieties to choose for cross-pollination?
The best way is to buy your plants from an established, reputable nursery, whether local or online. They should be able to recommend cross-pollinating varieties (online catalogs often list blueberry pollination recommendations in the variety’s description).
If you can’t get a specific recommendation, then compare the chill hours requirement of the varieties you’re considering for cross-pollination. The chilling hours requirement is simply the amount of cold a fruiting plant must be exposed to before it will break winter dormancy.
So let’s say you’re considering two varieties for mutual cross-pollination. Variety A has a chill hours requirement of 800 hours, and variety B has a requirement of 600 hours.
The two varieties aren’t ideal cross-pollinators because variety B will likely begin to bloom considerably ahead of variety A.
On the other hand, if A required 800 hours, and B required 750, then that’s pretty close, and odds are good that the two varieties will be good cross-pollinators. (The chilling hours requirement can also be a good indicator of whether a plant will do well in your area.)
Also remember that plants can only pollinate other plants of the same species.
Rabbiteye blueberries won’t pollinate lowbush, and lowbush won’t pollinate highbush, etc. So if you happen to live in a borderline area where you can grow two different species, just keep in mind that each species will need pollinators of the same species.