Blueberries

Darlene writes~ Could you give me some help with our blueberry bush. Four years ago I planted two of them. They haven't died but they won't grow either! They are only about 5 inches tall. This year I planted another one and the same thing. I've moved them this spring to see if that would help. I feed them. What am I doing wrong? We live in zone 4 if that makes a difference. Thanks for any help you can suggest.

A. I have never grown them so did a little research [check pH and soil]:

Blueberries are a good fruit crop for home gardens because they require little space. Blueberry plants require highly acidic [!] soil conditions for best results, and well supplied with moisture. Soil pH should be between 4 and 4.5 and contain at least 4 to 7% organic matter. With loam soils, it is suggested that plants be grown on raised beds, 4' wide and 9" high for better water drainage. Such beds are not needed for production on sandy soils.

It is very important to test soil for pH, nutrient status and organic matter content before preparing soil bed. Test it twice; once before soil preparation and acidification, and once after sulfur and fertilizer have been added. Further adjustments may be necessary. Increase soil organic matter by adding grass clippings, manure or leaves (not red maple or beech) according to soil test recommendations. Incorporate the materials into the top 4-6" at least one year before planting.  If soil pH is above 4.5, apply granular sulfur to lower soil pH. The material should be well mixed throughout the top 4" of soil, three months before planting.

At planting, dig a hole 18 x 18" and mix 1 cubic foot of peat moss with top soil until the hole is filled 4" from the top. Set the plant and cover the roots with the remaining peat-soil mix. Set plants 5' apart with rows 10' apart. Apply 4" sawdust or wood chips in a 2' wide band after planting, and maintain a 4" depth and 4' band over the life of the planting.

Blueberry bushes have very shallow root systems thus are very sensitive to water fluctuations. They need at least 1-2" of water per week. In dry seasons, supplemental watering is essential to obtain good yields of high quality products. Do not water after early September unless soil is very dry.

Blueberry plants begin to produce fruit in the third season; however, they do not become fully productive for about six years. Once in production, it is necessary to protect the fruit from loss to birds. They are generally not hardy when temperatures drop below -20 degrees F.

Blueberry plants normally do not need to be pruned for the first three years. Remove blossoms that appear in the year of planting and second year after planting to stimulate vigorous growth. During the fourth year, the dormant plants should be pruned in mid-March. At this time, remove dead and weak branches and thin wood with small buds. Prune interior crossing branches to admit light and air to the center of the plant.

In subsequent years, thin out older branches to force new growth. Tall-growing branches can be headed back and thin branches removed. Flower buds of blueberry bush are produced on tips and down the second year old shoots. Blueberry bushes tend to produce smaller berries when they are overloaded with fruits, making it important not to have too many flower buds.

Generous use of mulches such as sawdust or peat moss will help control weeds, conserve moisture and keep roots cool. Increased organic matter from decomposing mulch will help improve soil structure and nutrient uptake of blueberry bush. Replenish mulch as needed to keep the mulch depth at 2-4".

Adapted and edited from Gary Gao, Ohio State University Extension, 2000.