blueberry plants! Site and Soil
Plant blueberries where they have full sunlight most or part of the day. The soil should be acidic (pH 4.5-5.5), well-drained and porous, and high in organic matter. They are shallow-rooted plants and must be irrigated, heavily mulched, or planted in soil with a high water table. However, they cannot tolerate standing in water.
Your county extension agent can help you test the soil (see "Extension Offices" at www.extension.umn.edu). If the soil is not acid enough, it can be acidified by:
Mixing equal parts of acid peat and garden soil. This should be done at least 6 months before planting.
Adding sulfur at the rate of 1 pound per 100 square feet. The soil can then be maintained by annually adding acid-forming fertilizer such as ammonium sulfate.
Using pine bark, pine straw or sawdust mulch two or three inches deep. Mulch also controls weeds and retains moisture.
Planting Your Blueberries
Early spring planting is recommended. Set the plants four feet apart in rows six feet apart. Blueberries have a very shallow root system, so plant at the same level as they are grown in the nursery. They will have a definite line that shows you the right depth. Firm soil, mulch, and water to set the roots.
To improve productivity, plant at least two varieties. Blueberries require cross-pollination.
Fertilizer
Fertilize in early spring. Apply a balanced fertilizer such as 10-10-10. Also, Azalea-Rhododendron fertilizer is good for blueberries.
When using mulch, a high nitrogen fertilizer is necessary since decomposing mulch removes nitrogen from the soil. In early spring just before the buds break, apply about 2 ounces (1/4 cup) of ammonium sulfate under the branches around each plant.
Pruning
Prune any time from leaf fall until growth begins again in the spring. From the time of planting until the end of the third growing season, remove only the dead or injured branches, and branches too close to the ground.
As the bushes come into bearing (usually in the fourth growing season), regular pruning is necessary. Remove dead or injured branches, branches too close to the ground, and trim back bushy twigs.
Pest Control
Blueberries are easy care plants that rarely require chemical intervention. Birds love blueberries, so cover with plastic netting supported by a light framework.
Remove overripe fruit and diseased branches. If insects become a problem, use Ortho Fruit and Vegetable Insect Control. For fungicide, use Ortho Captan or Benomyl.
Winter Protection
Face it, in Minnesota we all need a little protection from the winter. Covering with straw in the fall reduces plant injury. Some gardeners use wire fence to contain this kind of mulch. Cover them up after the plants have been subjected to a few good frosts.
As always, if you have questions about when, where and why to care for your blueberries (or any other kind of plant!), call the greenhouse and ask one of our experts.
