February 27, 2004 at 10:10 a.m.
Several gardeners have asked me about raising blueberries. Some years ago I wanted to plant blueberries, rather than add to my raspberry patch. I received three plants as a gift, but they didn’t even last the summer. I talked with Rod Elmstrand, who at that time was the Chisago County Extension Educator. He also operates a u-pick blueberry farm between North Branch and Isanti on County Rd. 5. He will be the instructor for the blueberry class at “Garden Fever” on March 6. He suggested I have my soil tested and we found out that the pH in my soil is much too high for blueberries. They grow best in an acid soil with a pH of 4.0 to 5.0.
One of the misconceptions about blueberries is that since they grow wild in the woods that they will grow well in the shade. If you have ever picked them in the wild, you probably found them in open and well drained areas.
Blueberries are in the heath family, which includes azaleas, rhododendrons and cranberries. They are tolerant of acid soil and have low fertility requirements. When heath family plants are grown on alkaline soil near foundations of homes (where lime leaches into the soil raising the pH) iron deficiency can become apparent. When soil becomes more acidic (lower pH), iron is more easily solubilized and absorbed.
Not all blueberries are created equal. Look for half-high varieties developed by plant breeders at the University of Minnesota. By hybridizing highbush blueberries (which aren’t hardy here) with our native blueberries, the U of M has developed several named cultivars that combine tasty fruit with winter hardiness.
Blueberries require two different varieties grown near each other for cross-pollination for best results. Chippewa is the exception to this requirement. If the brilliant red foliage is important, be sure to plant Northcountry along with another variety, such as, Northblue, St. Cloud or Polaris for cross-pollination. If you are looking for an exceptionally small shrub then plant Northsky, as it gets to be only 1 foot tall. Other varieties can grow from 3-4 feet tall. Again, there must be another variety planted nearby for best production.
The planting directions may be different for you because your soil may be friendlier for raising blueberries. I dug the holes about two feet deep and about 2-feet in diameter. I planted my blueberry plants in a row about six feet apart. Next, I mixed the soil I had dug out with acid peat in about a 1:1 ratio. You can mix about a cup elemental sulfur in the peat/soil mixture before planting the bush. Alternatively, you could apply one pound of elemental sulfur per 100 square feet of blueberry growing space or mix two pounds of elemental sulfur for every 50 cubic feet of soil. The purpose of the sulfur is to lower the pH of the soil to the desirable pH level. Other good forms of sulfur include iron sulfate. Do not use aluminum sulfate as high rates of this compound can be toxic to the roots.
Once you have gone through all of this, you are ready to enjoy raising blueberries. They don’t really require any more maintenance than other plants. They need to be watered on a regular basis due to their shallow root system. I fertilize with an acid fertilizer about every two weeks. I also mulched around the plants with pine needles. You could also use a shredded wood chip mulch to help retain moisture.
Remember, you are not the only one who likes blueberries. The birds and deer enjoy them also. I used a net over the plants to discourage the birds, and human hair to deter the deer. So far, so good.
There are three varieties that you can order from us as bare root stock. Chippewa is a midseason, compact, upright bush to 4 ft high. Fruit is medium large, very light blue, firm, and very sweet. Developed for the soil and climate of central and northern Minnesota. Parentage includes some of the most cold hardy selections known. Horticulturist Dave Wildung says the plants are more upright than Northblue and produce slightly better at the North Central Experiment Station at Grand Rapids. "It will be a useful addition in commercial plantings in cold regions, as well as in residential plantings and gardens.” North Country is short in stature, plant maturing at 20" high. Fruits are small and flavorful, compared to wild berries. Good for home gardener use. This cultivar is also an outstanding ornamental with profuse flowering and brilliant fall colors. Northblue is a semi-dwarf bush, growing to a height of 3-4 ft. Fruit is large, dark blue, with a "wild" blueberry flavor. Released by the University of Minnesota as a commercial variety where productivity of normal highbush cultivars is poor due to cold winter temperatures or inadequate winter protection. It is quite productive for its size producing between 3 and 7 pounds per bush in Minnesota tests.
Brochures are available for Bonanza 2004 “Garden Fever” which will be held at Maranatha Church in Forest Lake on March 6. Call or email to receive a brochure or if you are interested in being a vendor, 651-237-3080 or [email protected]. Forms are also now available to preorder bare root strawberry, raspberry, blueberry and grape plants. Many of these are cultivars developed at the University of Minnesota and used by commercial growers, but hard to find for home use.
You can view the brochure and order form on the web at: http://www.extension.umn.edu/county/Chisago/news/brochure2004%20final.pdf