Blueberries are part of the latest rage in health foods today because they are the richest food source of phytonutrients called flavonoids esp. anthocyanins. These purple and dark red pigments are natural antioxidants that are strongly anti-inflammatory, antiallergic, antiviral and anticancer agents. Flavonoid-rich foods improve the function of the cells that line the blood vessels (endothelial cells) enabling the cells to produce more nitric oxide. Blueberries in particular have been found to protect against cardiovascular disease specifically by relaxing the blood vessels & improving blood flow.
Wild or low bush blueberries were a staple in the Native American diet long before the colonists arrived. Blueberries were eaten fresh or dried then mixed with meat to make pemmican or mixed with cornmeal, honey and water to make a pudding. The juice was used to make cough syrup while the leaves were made into a tea meant to fortify the blood.
Blueberries are one of the 3 fruits native to North America. There are more blueberry species native to North America than any other continent—they are northern and southern high-bush, low-bush, half-high and rabbit-eye. The blueberry is in the genus Vaccinium and is closely related to the azalea, cranberry and rhododendron. Blueberries are sometimes mistakenly referred to as huckleberries, which are actually a different genus—Gaylussacaia. America now grows over 90% of the blueberries in the world. The problem with domestic blueberries is that they are ranked 14th in the most chemically laden food by the Environmental Working Group.
Blueberries are a deciduous shrub that are widespread in pine, spruce and beech forests. They ripen from June to August. The leaves in fall become a vivid red making it very decorative in any home garden. The low bush varieties prefer colder conditions while the high bush prefer more moderate conditions so be sure to check which varieties grow successfully in your area. Blueberries will live and produce for 40 to 50 years but it will take 3 to 4 years to produce after planting and they need to be maintained by watering, fertilizing and pruning when necessary.
Blueberries are resilient but will not produce well unless they are in ideal conditions. The soil pH is the single most important factor in selecting a blueberry site. It is best between 4.5 and 5.5 (even down to 3.5). If the pH is above 6 or the soil is heavy clay it will take time, effort and money to improve the location for blueberries.
Choose a site that gets full sun at least ¾ of the day and is not located near cement sidewalks or walls that might leach lime into the soil & raise the pH.
Blueberries thrive best in a rich soil so dig in an acidic humus such as peat moss to a depth of 8 to 10 inches and let sit for several weeks. Then do a soil test from several spots to make sure the pH is in a good range for the blueberries. You can increase the acidity of the soil with an application of acidic nitrogen fertilizer like ammonium sulfate, sulfur granules, iron or magnesium sulfate depending on the Penn State Soil test. In home gardens, it helps to plant blueberries in mounds or raised beds because it is easier to regulate watering and soil characteristics to insure healthier plants. The raised beds are easy to cover with wood chips (pine, spruce, beech) that help keep the pH in range, reduce weed growth, prevent moisture loss and overheating during the summer heat. The blueberry root system is very shallow, compact, intertwined and develops in a small area. Therefore hand weeding is better than cultivating. Add mineral fertilizers more often in smaller amounts to avoid spikes in nutrients and to lessen root burn—adding humus and mulch enriches soil gradually.
Space the plants 4 to 8 feet apart depending on the variety. The first year remove flower buds. In the following years remove old, weak and diseased branches. After fruiting the 3rd year prune to open up the inside of the plant and remove the oldest, darkest branches to promote new vigorous branching and flowering. Blueberries have a large numbers of flowers and so many bumble bees are needed for pollination to get good fruit set. Some varieties of blueberries are less attractive to bees (Duke variety) than others (Weymouth variety), depending on the quality and quantity of nectar, flower color and sugar content. It is recommended to mix several varieties for better pollination, larger berries,longer harvesting season and varying tastes of the blueberries. Whether fresh or frozen, the pale, powder-like coating on blueberries called “bloom,” should remain until just before eating, as it helps protect the fruit from damage and disease.
Certified Master Gardeners are local volunteers trained by Penn State to answer Horticulture questions with properly researched information. For a “best practices” answer to your question, call Penn State Jefferson County Extension at 849-7361, Ext 508, e-mail JeffersonMG@psu.edu, or mail your question to 186 Main Street, Suite 3, Brookville, PA 15825.
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