Wondering how to grow the sweetest blueberries and avoid a tart or bland harvest? No worries. With a little bit of help, you can get your blueberry shrubs to produce sweeter fruit than ever this year!
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Best (and Worst) Blueberry Varieties for Sweetness
Before we get into how to grow the sweetest blueberries, it’s important to consider the different types of blueberry shrubs out there. How sweet your harvest will be depends a lot on the type of blueberry plant you go for!
As you may know, there are four basic types of blueberries:
- Highbush blueberry plants (Vaccinium corymbosum)
- Lowbush blueberry plants (Vaccinium angustifolium)
- Half-high blueberry plants ( cross between highbush and low bush)
- Rabbiteye blueberries (Vaccinium virgatum)
Sweet Half-Highs and High Bush Varieties
The plump blueberries you’ll find in your local grocery store usually come from a highbush variety. This is the more commercially important variety, which has been selectively bred for factors like berry size, sweetness and shelf life.
Our farm is in zone 4 and the half-highs were considered sweet and adapted for a zone 4 climate back when we started our farm in 1998. We planted 500 half-high blueberry bushes in 1998, which are still thriving more than 25 years later. Our mix included Polaris, Northblue, St. Cloud, Northland, and Chippewa.
The climate has changed a bit since 1998 and the cultivars have expanded, so we added quite a few high bush varieties to the mix over the years (primarily Bluecrop and Duke).
As far as sweetness goes, St. Cloud is considered one of the sweetest half-highs (smaller berries however), and blue crop is a standard highbush that has very sweet berries.
Friendship (a Wisconsin variety) is more similar to the tarter flavor of wild blueberries and Elliot is a late ripening high bush that is considered to have tart berries.
The Plant Kingdom has put together a chart that is helpful in selecting blueberry varieties for ripening time and for sweetness.
I also put together the video below which goes over the characteristics of the hardier blueberry plants that grow well in Northern climates.
Tip: If you want to grow your blueberries in pots or containers I would stick with the half-high varieties. Some of the high bush varieties grow to 6-7 feet tall which is cumbersome in a container.
Blueberry Plant Varieties: Selecting Hardy Varieties for Northern Climates (Zones 3 and 4)
Lowbush Blueberry Varieties
Lowbush blueberry cultivars aren’t as extensively bred as their highbush cousins. In fact, if you like to pick wild blueberries, those are considered lowbushes!
Wild blueberries tend to be smaller and generally quite tart. Perfect for baked goods, but not as sweet for eating out of hand.
Rabbiteye Blueberry Varieties
Lastly, popular for warmer areas due to their better heat tolerance, rabbiteyes are another good choice if you like sweet blueberries and live in a warmer climate. The skin on these relatively large fruits is a bit thicker than that of highbushes.
Some scientific studies suggest rabbiteyes are actually even sweeter than highbushes, but others don’t agree. It might just be a tie between the two, depending on the exact cultivar you go for.
All this being said, there are many more things to keep in mind when it comes to blueberry sweetness. There are many different cultivars to choose from, but, it is actually more important that the growing conditions are right. If they aren’t, your harvest can turn out disappointing even if you choose the sweetest blueberry cultivar in existence!
Best Blueberry Fertilizer for Enhancing Sweetness
In my years of growing this fruit, I’ve learned that there’s one factor that influences blueberry sweetness more than any other. It’s potassium! In fact, this humble mineral is one of the most important in ensuring any fruit tastes good.
Basically, when plants like blueberries enter the ripening stage, their potassium use soars. Potassium helps ensure the fruit ripens at the right pace, acquires the right color and takes on its typical flavor. Most importantly in this case, it also plays a huge role in the eventual sugar content of your blueberries.
To help make sure your harvest doesn’t turn out tart or bland, try using a special blueberry fertilizer. It should be high in potassium (the K in the N-P-K ratio, which stands for potassium), and will usually also contain elements that help acidify the soil, which is just how blueberries like it.
You can apply fertilizer on a regular basis from mid-spring onward. It’s especially important to keep up with your fertilizer schedule once your blueberry shrub has begun blooming and developing fruit.
Growing Tips for Sweetest Blueberries
Aside from potassium, there are a few other important things you should keep in mind if you’re wondering how to grow the sweetest blueberries. Specifically, don’t forget about:
- Water: Although your blueberry bushes will need plenty of water – about an inch per week – too much moisture can negatively affect berry sweetness. Blueberries tend to grow huge during wet years, but they may also be bland.
- Sunlight: Although they’re not necessarily fans of very high temperatures, blueberry shrubs love growing in full sun. Their fruit production can be affected if they don’t get enough light.
- Soil acidity: Blueberry shrubs like their soil nice and acidic, with a pH of 5 or under. If your soil is more alkaline, you may have to use an acidifying amendment to avoid issues.
- Harvesting: For the best flavor, you should leave your blueberries on the plant until they’re fully ready to pick. You can find out more about pinpointing the perfect moment in the post on how to tell when blueberries are ripe.
Did you know? Research suggests that altitude may also have a positive effect on blueberry sweetness levels, at least in rabbiteye varieties.
Saftner, R., Polashock, J., Ehlenfeldt, M., & Vinyard, B. (2008). Instrumental and sensory quality characteristics of blueberry fruit from twelve cultivars. Postharvest Biology and Technology, 49(1), 19-26.
Zeng, Q., Dong, G., Tian, L., Wu, H., Ren, Y., Tamir, G., … & Yu, H. (2020). High altitude is beneficial for antioxidant components and sweetness accumulation of rabbiteye blueberry. Frontiers in Plant Science, 11, 573531.