Blueberries and the University of Minnesota Horticulture Days

Our work doesn't stop when we close up the shop for the season.

 Rest assured that Gracie's Plant Works is out there, 

working for you throughout the entire year, learning, gaining and sharing information, all

aimed to enhance and increase your success in the garden.

Patty and I attended the University's Horticulture Days last Wednesday

at the Grand Rapids growing station.  This is the northernmost horticulture growing

and research station in the United States, so the testing performed there is of particular

interest to those of us in Zone 3 here in northern Minnesota.

And, since it's very timely, this info that I'm about to give you, you might

just want to take some time to read it carefully and 

increase your blueberry harvest next summer.

 Test plots of new blueberry cultivars.  

That's Patty in the background, eating blueberries, by the way.

Who wouldn't love to see a plant this full of berries in their yard this late in the season?  Indeed,

this photo was taken on August 27th, 2014, and the plant was still loaded with unripened blueberries.

It may be awhile until this new cultivar is released for the market, but we'll be following 

the progress closely.

The University of Minnesota has been developing blueberry cultivars since the very early 1960s, so it's quite safe to say that they have a bit of experience. In fact, the breeding done by the UofM crossing low-bush and high-bush plants has yielded plants that exhibit the best traits of each type to result in a best of both worlds scenario.

We would like to give credit to Professor Dave Wildung (retired 2007) for presenting the lecture on blueberries.  Dr. Wildung created seven (7) new blueberry varieties in his career, and we were fortunate to be in the presence of a 'true authority' on the subject.
 Some notable nuggets of information we took away from our conference

about blueberries and how to grow them successfully this far north:

First and foremost, blueberries fruit on the growth of the year, or, in other words,

they do not fruit on old wood like raspberries.  Next year's crop begins growing in

August or September of the current year, so you never, never, never, ever prune or

trim blueberry bushes anytime after July 4th.  

Doing so will shut the plant down and it won't have enough time to regrow before winter.

WHEN you prune, you are only to cut out old wood so as to increase airflow through the bush, enhance light penetration, and perhaps to shape the bush.  "Old wood" is defined as gray and bark that is sloughing, or peeling away.  These old wood branches should be pruned or cut down to the ground level.

INCREASING YOUR ODDS FOR A BOUNTIFUL HARVEST

Photo courtesy of www.beautifulwildlifegarden.com

Songbirds will eat your blueberries, as will game birds such as grouse.
Chipmonks and squirrels love blueberries, too.  

The most damage, however, will be done by Old Man Winter and 

Mother Nature's posse of herbivores in the northwoods.  

The good news is that blueberry bushes seldom suffer from

insect infestation.

Have you ever stopped to consider why the high bush and half high blueberry bushes are less prolific in their yields in our neck of the woods, while the true lowbush varieties are generous in their fruit production?  The answer is that, for blueberries, the critical temperature for winter kill is 

-25 to -30 degrees F for several days in a row.  Um-Huh.  We all have experienced THAT.

So, any parts of the bush that are under snow will be protected from the extreme temps and will not winter kill.  Anything above the snowline will.  It becomes clear that the bits above the snow (which hold next season's fruit) will be frozen out, or they'll be nipped off and pruned by rabbits and deer.  This is what you call an "a-ha moment".

That said, planting blueberry bushes requires some aforethought as to location.  You should choose a location that will naturally drift in with snow and cover the entire plant, or you can shovel snow on top of the plant until it is tucked in under a blanket of insulating snow for the winter.

Plant your low-bush or half-high plants 2 feet apart in rows 5 feet apart.

It is also prudent to have two or more varieties planted in the same area.  Blueberries are self-fruitful and don't need a second variety like apple trees do, but two varieties will encourage cross-pollination, which will yield larger and better tasting berries.

 You also want a sunny location with good drainage.  Soil preparation is critical for success when planting blueberries, so have a soil test performed and know your pH.  Blueberry bushes will only require fertilization to keep the acidity of the soil high (i.e. the pH low).  If your soil is

full of clay and a pH of 7 or over, you will need to seriously amend it 

or forget about growing blueberries.

6.5 pH and lower is needed, so get a bag of sphagnum or peat moss,  and mix in the soil to a ration of 50% soil and 50% peat or sphagnum.  The moss will add organic matter to the soil and

will assist in holding water for the newly planted bushes that will allow them to establish themselves.

Photo courtesy of www.onthegreenfarms.com

Immediately after planting, mulch with pine needles or bark to keep the roots cool and moist.  

The majority of a blueberry bush's roots are very near the surface of the soil,  

and drying out is to be prevented.

As part of the research station's mission to record performance by cultivar, the result of the 2014 growing season for a particular type of blueberry (developed, natch, by the U of M) 

is 9 pounds per plant. They also compare the yields to other cultivars they have developed, and this year, North Country, another UofM-developed cultivar, yielded 1.5 pounds per plant.  

You can bet that Gracie's Plant Works will have the high yielding variety next spring.

The blueberry lecture was the first of several, plus our own meanderings about the research station.  Look for new posts on each topic coming soon!

Happy gardening,

Kathy and Patty