University of Vermont Extension 
Department of Plant and Soil Science

Winter/Spring News Article
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CHOOSING BLUEBERRIES

Dr. Leonard Perry, Extension Professor
University of Vermont
 
Blueberries are a great choice for their fruit, as well as shrubs for your landscape.  Their fruits are easy to pick, freeze, have many uses, and stand out among fruits for their high content of antioxidants—those chemicals that slow aging and help your immune system fight infections.  Blueberry bushes are easy to grow, have few problems if any, with attractive glossy green leaves in summer turning a beautiful red in fall.  When choosing which blueberries to grow, first determine which group you want.  There are many cultivars to choose from within each of these groups, varying mainly in time of bloom and fruit size.
           
You’ll want to choose at least 2 if not 3 different ones for cross pollination, unless they are one of the few listed as “self fertile” or “self-fruitful”.  Make sure to choose ones from the same group as, for instance, a lowbush won’t pollinate a highbush type.  Make sure too that they are listed to bloom at the same time.  You’ll find cultivars (cultivated varieties) 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.
           
There are five main groups of blueberries, representing three main species.  Three of these groups are suitable for northern gardens.  In the South you’ll see rabbiteye and southern highbush cultivars, which aren’t hardy in the north.  They can’t survive below about 0 to -10 degrees (F) minimum winter temperatures.
    
Hardiest of the blueberries, the lowbush (Vaccinium angustifolium) are the fruits those in colder climates love to pick from the wild. Native Americans dried the berries and pounded them into “moosemeat” -- an ingredient they used to make pemmican. Wild lowbush blueberries are grown commercially in some northern states, particularly in Maine. They’re grown more in the coldest northern regions, not merely as they are more hardy (zones 3 to 7), but that being only a foot or so high and usually under snow they survive better than highbush cultivars.  Space these about 2 to 3 feet apart.  Gardeners who grow wild blueberries in their backyards can expect about a pint of berries for each foot of row in late July to August.
           
There are only a few cultivars for fruit, and a few selected for their ornamental use as low, massed groundcovers or even as a plant for large containers.  If growing in containers, give some winter protection such as an unheated garage, or bury pots (not tops) in the compost pile.  ‘Top Hat’ is a mounded cultivar under two feet tall and wide.  ‘Burgundy’ has a beautiful dark red fall leaf color, and grows about one foot high and about three feet wide.
           
The Northern highbush (Vaccinium corymbosum) is the most popular blueberry plant in many areas, both for home gardeners and commercial growers. They’re usually the ones you find at u-pick farms.  The bushes grow from 6 to 15 feet high, and produce large berries midsummer in zones 4 to 7 usually (-20s to 10 degrees minimum winter temperatures). Yields vary widely among the cultivars, but most gardeners can expect from 5 to 15 pounds per bush. 
           
Although less hardy than the lowbush, some cultivars of the highbush grow well in zone 3 (-30 degrees) when planted in a spot sheltered from the wind.  They usually grow in areas with growing seasons of at least 160 days between frosts.  Many cultivars require a chilling period of 600 or more hours below 45F, making them unsuitable for hot and mild climates.
           
Some of the more popular highbush cultivars include the early-season ‘Duke’, ‘Bluecrop’ in mid-season and ‘Jersey’ in late mid-season, ‘Nelson’ in late-season, and ‘Elliott’ in very late- season. If you only have room for one, look for the self-fruitful ‘Bluetta’.  For really red fall leaves look for ‘Brigitta’, ‘Hardyblue’, ‘Legacy’, or ‘Reka’.  Some of the largest berries can be found on ‘Chandler.’

Crosses between highbush and lowbush blueberries have resulted in several lower cultivars than highbush, but taller than the lowbush, which are often termed “half-high hybrids”.  Being shorter (3 to 4 feet) and so more protected by snow in the north, they often survive better there than many highbush cultivars.  They grow in zones 3 to 7.  Yields on these generally range from 2 to 8 pounds per bush.
    
Most of the half-high cultivars are self-fruitful, but even these will have larger fruits and better yields if more than one cultivar is nearby.  ‘Chippewa , ‘Polaris’, and ‘St. Cloud’ require another cultivar for cross pollination. Some popular cultivars in this group include the early ‘Patriot’, the early mid-season ‘Northland’, and the mid-season ‘North Sky’.  ‘Friendship’ is one of the few late-season cultivars.
           
When choosing blueberry bushes, to make their culture even easier, look for ones with some disease resistance, particularly to “mummyberry” and stem canker.  Mummyberry causes fruits to turn pink prior to ripening, shrivel and fall off (these are termed “mummies”).  Stem canker may cause cracks in the canes and then death, particularly on Northern highbush cultivars.
           
When planting, allow sufficient space for mature growth—5 to 6 feet apart for the highbush, 4 to 5 feet apart for the half-high, and one to 2 feet apart for the lowbush. You can find more on blueberry culture in the Fruit Gardener’s Bible, by Lewis Hill and Leonard Perry.

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