University of Vermont Extension 
Department of Plant and Soil Science

Summer News Article


BASICS OF GROWING BLUEBERRIES

Dr. Leonard Perry, Extension Professor
University of Vermont
 
 
Blueberries are one of the most popular and healthful fruits, are easy to grow, and can be grown as an ornamental shrub.  Many have colorful red fall leaves. If you like eating blueberries from the store or picking your own, consider if you might have the space and conditions for growing them in your landscape.  The most important aspects for growing blueberries successfully are choosing hardy varieties and having the right soil.
           
There are five main groups of blueberries, representing three main species.  The northern highbush (Vaccinium corymbosum) and lowbush (Vaccinium angustifolium) are the main species for northern gardeners, as well as hybrids of these called “half-high”.  While the highbush reach from 6 to 15 feet high, depending on climate and cultivar (cultivated variety), the lowbush only reach a foot or so high.  The half-high reach from 3 to 5 feet high.  These northern groups need sufficient cold to produce flowers, then fruit, so are not suitable for southern gardens.  There you’ll see rabbiteye and southern highbush cultivars.  There are many cultivars to choose from within each of these groups, varying mainly in time of bloom and fruit size.
           
When choosing blueberry cultivars, you’ll want at least 2 if not 3 different ones for cross pollination unless they are one of the few listed as “self fertile”.  Make sure to choose ones from the same group as, for instance, a low bush wont pollinate a highbush type.  Make sure too that they are listed to bloom the same time.  You’ll find cultivars listed as early, mid, or late season.  Although this often refers to ripening of the berries, relative bloom time is similar except for some commercial cultivars.   So the bees can move the pollen among your different bushes, plant them near each other or preferably intermixed.
           
Other than getting the right cultivars, you’ll need the right soil for blueberries to succeed.  They like plenty of organic matter in the soil, and well-drained soils so roots don’t rot.  Perhaps the most important point though is to have acid soils—ones with a low pH of 4.5 to 5.2.  You can probably get by with a pH of up to 6.0 if you use plenty of peat moss which is acidic.  Sulfur also can be used to lower the pH.  If soils are more alkaline (most plants grow best with a pH of 6.0 to 7.0—the latter being neutral), it may be more work yearly to try and lower the pH than worth it.
           
One solution if the soil pH is too high is to get a shorter cultivar, such as lowbush or half-high, and plant in a container.  Just make sure it is large enough, perhaps 15 to 20 gallon size, or 18 to 24 inches wide and 12 to 15 inches deep.  You can plant container and all right in the ground.  If left above ground, make sure to bring into an unheated shed or garage over winter that wont allow the soil to freeze.  Ample ground heat protects roots in the ground during winter, something roots above ground in pots don’t get.  Container blueberries also are great for small gardens. When planting in containers, use half peat moss and half potting soil.
           
Once you have the right cultivars, and soil, plant as you would other shrubs.   Give enough space—at least 5 to 7 feet apart for the highbush, 3 to 5 feet apart for the half-high, and 2 to 3 feet apart for the lowbush.  Add plenty of peat moss or compost, or both, when planting.  Blueberry roots are near the surface and sensitive to drying out, so don’t allow them to dry before planting and water well once planted.  Keep them well-watered until established, and even later when droughts.  Several inches of mulch helps retain moisture, and helps prevent weeds.  Hand pulling weeds is best so not to damage their shallow roots with a hoe.
           
Since blueberries usually begin bearing fruit when 4 to 5 years old, buying older and larger plants will give you fruit in fewer years.  You don’t really need to prune bushes, except to remove broken or rubbing branches, until they are much older.  They do need some fertilizer, such as a cup of 5-3-4 or similar for young plants, more for larger mature ones.  Apply this in early spring, and perhaps again in late June.  Don’t apply much later so plants will harden properly for winter.  Also you can use acidic fertilizers as you find for azaleas and hollies.

If leaves are reddish or have reddish dots, and are overall light green to yellowish, they may need more nitrogen such as from ammonium sulfate.  If leaves are light green between veins, this is a common symptom indicating iron deficiency.  This, in turn, may mean the soil pH is too high.  Check it first, and correct if needed, and the iron deficiency may be solved too.

Animals don’t really bother blueberries, but they are a favorite food of birds.  You may try scare tactics such as noise emitters and bright balloons and objects hung among plants, but the best method most end up using is tight bird netting over plants.  This netting is black and of thin plastic strands that aren’t really obtrusive or even noticeable from a distance.

Whether you grow your own or just pick blueberries locally, berries are simple to just wash and freeze for use through the rest of the year.  Eating more blueberries, even making and drinking blueberry juice, you’ll realize a range of health benefits.  Not only are they the highest fruit in antioxidants, but they contain other compounds as well that help your immune system fight infections,  help to reduce belly fat, promote urinary tract health, preserve vision and brain health, reduce the risk of heart disease, aid digestion, help prevent certain cancers, and serve as an antidepressant to keep you in a good mood. And you thought blueberry pie just tastes good!
 

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