WW-02241        

Commercial Blueberry Production in Minnesota and Wisconsin

Home  |  Choosing Cultivars  |  Selecting and Preparing a Site  |  Planting

Choosing Cultivars

Copyright ©  2012  Regents of the University of Minnesota. All rights reserved.

The blueberry cultivars best adapted for Minnesota and Wisconsin produce flavorful fruit on short-statured bushes that can survive typical winter temperatures. Table 1 summarizes each cultivar's characteristics. All listed cultivars require an average of five years before producing a large harvest and up to ten years, or perhaps more, before reaching mature size.

Table 1: Characteristics of half-high blueberry cultivars

cultivar	zones	plant characteristics1	fruit yield	fruit characteristics2
Northblue	3-5	20-40 inches tall 30-60 inches wide	3-12 lb./plant	Large, dark blue, firm berries; good fresh flavor; superior processed flavor.
Northsky	3-5	20-40 inches wide 10-30 inches tall	1-5 lb./plant	Medium, sky-blue berries; sweet, mild,aromatic fresh flavor; superior processed flavor. Ripens with 'Northblue.' Yield and berry size benefit from cross-pollination.
Northcountry	3-5	15-40 inches tall 30-60 inches wide	2-7 lb./plant	Medium, sky-blue berries; sweet fresh flavor similar to wild lowbush blueberries; ripens 5 days earlier than 'Northblue.' Yield and berry size benefit from cross-pollination.
St. Cloud	3-5	30-50 inches tall 40-60 inches wide	3-9 lb./plant	Medium, dark blue, firm berries; sweet flavor, crisp texture; good storage capability;ripens 5 days earlier than 'Northblue.' Requires second cultivar for pollination.
Polaris	3-5	20-50 inches tall 30-60 inches wide	3-10 lb./plant	Medium-large berries; very firm and very crisp texture; intense aromatic flavor; excellent storage capability; ripens 7 days earlier than 'Northblue.' Requires second cultivar for pollination.
Chippewa	3-5	20-50 inches tall 30-60 inches wide	3-12 lb./plant	Medium-large berries; sky-blue color;sweet flavor; firm fruit; ripens with 'Northblue.' Yield and berry size benefit from cross pollination.
Northland	3-5	30-50 inches tall 40-60 inches wide	3-12 lb./plant	Medium-large berries; mild flavor. Ripens 3 days after 'Northblue.'
Bluetta	5	40-60 inches tall 40-60 inches wide	3-12 lb./plant	Medium-large berries; sweet, aromatic flavor. Ripens 7 days earlier than 'Northblue.'
Patriot	5	40-60 inches tall 40-60 inches wide	3-12 lb./plant	Very large berries; tart, aromatic flavor. Ripens 5 days earlier than 'Northblue.'

¹For plant height, width, and yield, the lower end of the range will be more likely in harsher climates, such as that of northern Minnesota. Blueberries are slow growing relative to other fruit plants and will not reach mature size for eight to ten years, even under optimal growing conditions.

²Ripening sequence is that observed at Becker, MN.

Plants

Most plants available from nursery sources are propagated by tissue culture rather than from cuttings. Young tissue-cultured plants are more vigorous than cutting-propagated stock and produce correspondingly higher numbers of flower buds, because of increased development of basal and lateral branches.

Several plant sizes are available, both bare root and in containers. Table 2 outlines the various types and recommended uses.

Table 2: Types of blueberry plants available

Type	Description	Application
liners	3-6"	nursebed
one year old	7-12" cup-sized rootball	nursebed or field planting
two year old	12-18" quart-sized rootball	field planting
three year old	18-30" gallon-sized rootball	field planting

Larger plants are ready for direct field planting in a prepared site. Small plants should be grown in containers or placed in nursebeds for at least one growing season before being transplanted to the field.

Nursebed

The nursebed is an intensively managed space designed to promote additional root and shoot development before field planting. Such a practice allows for the purchase of smaller, less expensive plants and thus reduces start-up costs. The nursebed is constructed by forming a raised bed of acid peat moss 8 to 10 inches deep. A support frame around the perimeter of the bed will hold the moss in place.

Transfer young plants to the bed and space eight to 12 inches apart. Remove containerized plants from their pots. Growing plants will require shading and protection from wind until they become acclimated to full sun and winds. Moisture levels must be monitored closely, and supplemental irrigation applied as needed. The use of drip tubing or soaker hose is preferable to overhead sprinklers.

The peat moss growing medium will not supply nutrients to the plants as soil might, so fertilize every two weeks during active growth with a water soluble acid-reacting fertilizer such as Peter's Acid Special (21-7-7) or Miracid (30-10-10). Micronutrient needs can be satisfied by adding a trace element mixture such as S.T.E.M. (soluble trace element mixture) at half strength to the fertilizer solution once a month. Follow label rates. Discontinue fertilizer applications in late summer when growth slows. Closely monitor soluble salts levels in the bed to prevent root damage.

Bedded blueberry plants need to be protected during winter. Snow is an excellent insulator and can be used to protect plants in the nursebed against injury caused by severe winter temperatures and drying winds. However, since timing and amount of snowfall is unpredictable, a mulch or artificial covering can be applied when plants go dormant.

Before covering plants, strip off any remaining leaves and apply a protective fungicide such as Captan. This will help prevent potential fungal infection. Uncontrolled rodents can also pose a problem. Commercially prepared poison baits containing zinc phosphide are convenient and easy to use. Controlling weeds within the nursebed and mowing the area around it will reduce rodent habitat.

The winter protection cover, consisting of two layers of plastic with a mulch layer between, may now be installed. First dig a shallow trench around the edge of the nursebed. Cover the plants with plastic. Place one foot of straw or hay on top and cover with a second sheet of plastic. Secure the border by laying edges of plastic in the trench and covering with soil. The plastic-straw-plastic sandwich will insulate the blueberry plants from extreme low temperature, prevent desiccation (drying out), and allow for easy removal the following spring.

Home  |  Choosing Cultivars  |  Selecting and Preparing a Site  |  Planting

Produced by Communication and Educational Technology Services, University of Minnesota Extension.

In accordance with the Americans with Disabilities Act, this material is available in alternative formats upon request. Please contact your University of Minnesota Extension office or the Extension Store at (800) 876-8636.