By Richard Jauron
Extension Horticulturist
Blueberries are attractive shrubs with flowers in spring, edible berries in summer and fall foliage in shades of yellow, orange and red. Blueberries can be grown in any home garden, but there are some special growing needs that must be met. Iowa State University Extension and Outreach horticulturists give helpful information on how to grow blueberries successfully in Iowa.
To have additional questions answered, contact the ISU Hortline at 515-294-3180 or at hortline@iastate.edu.
Can blueberries be successfully grown in Iowa?
Blueberries can be successfully grown in Iowa. However, they do have special growing requirements.
Blueberry plants require a sunny location and a well-drained soil high in organic matter. Avoid wet, poorly drained sites. Blueberries are susceptible to root rots in poorly drained soils.
Soil pH is also important. Blueberries require acidic soils with a pH of 4.0 to 5.5. Since the pH of most Iowa soils is above this range, the soil pH must be lowered to successfully grow blueberries.
How do I lower the soil pH for blueberries?
Home gardeners can lower their soil pH by adding sphagnum peat moss to the soil. Sulfur can also be used to acidify the soil. Sulfur should be incorporated into the soil a year before planting as it reacts slowly with the soil. Aluminum sulfate should not be used to acidify the soil as large amounts of this material can be toxic to blueberry plants.
Which blueberry varieties perform well in Iowa?
Highbush and half-high blueberries can be grown in Iowa. Plant two or three different cultivars to ensure adequate pollination and fruit set.
Highbush blueberries are 6 to 8 feet tall at maturity. Suggested cultivars for Iowa include ‘Duke’, ‘Patriot’, ‘Bluejay’, ‘Blueray’, ‘Bluecrop’, ‘Rubel’, and ‘Elliott’.
Half-high blueberries usually grow only 2 to 3 feet tall. Plants produce small to medium sized berries.Suggested cultivars are ‘Polaris’, ‘Northblue’, ‘Northcountry’, ‘Northsky’, and ‘St. Cloud’.
How do you plant blueberries?
Early spring is the best time to plant dormant, bare-root blueberries. Soak the roots of bare-root plants in water for about an hour before planting. Prune back the plants by half by removing the small side branches and by heading back the main branches.
Potted or container grown blueberries can be planted from spring to mid-summer. Little or no pruning should be necessary. Carefully slide off the container just prior to planting.
When planting, dig a wide, shallow hole. Set the plant at the same depth as it grew in the nursery or pot. When using sphagnum peat moss to acidify the soil, backfill with a mixture that is half soil and half moistened peat moss. Moisten dry peat moss before mixing with soil. If not amending the soil with sphagnum peat moss, backfill with the original soil. After planting, thoroughly water each blueberry plant. Highbush blueberries should be spaced 4 to 6 feet apart. A 3 to 4 foot spacing is adequate for the smaller half-high blueberries.