Blueberries in the Garden and the Kitchen

Blueberries in the Garden

Blueberries (Vaccinium spp.) are native to the Americas. Historians believe that dishes with this fruit were probably served on the first Thanksgiving. In Pennsylvania, the gardener has many choices of cultivars. Lowbush blueberry (Vaccinium angustifolium) is a short mat-forming shrub ranging from 14 to 24 inches tall. It is a very cold-hardy crop with small, sweet berries. It is found mostly north of Pennsylvania, in New England, and in Canada. Cultivars of this wild blueberry include ‘Brunswick’ and ‘Burgundy.’ Highbush blueberries (Vaccinium corymbosum) are the type most likely to be grown in Pennsylvania. They are large upright deciduous shrubs that produce large berries on canes growing from a central crown. This shrub can be 5 to 8 feet tall and wide at maturity or even larger. Many cultivars exist and are defined by the timeframe that berries ripen: early, early midseason, midseason, mid-late season, and late season. While these blueberries are self-pollinating, research shows that growing more than one cultivar creates larger berries and crops. One can thus be rewarded by selecting cultivars that provide ripe berries from late June through September. Penn State cultivar analyses can be found in the article Blueberry Variety Selection in the Home Fruit Planting.

Relatively recently, new hybrids have been developed as a cross between the lowbush and highbush species and are called half-high. Traits include the cold hardiness of lowbush, the large berries of highbush, and a much more manageable size for the home gardener (3 to 5 feet tall and wide). However, research these hybrids with regard to their self-fertility. For example, it is suggested that Vaccinium angustifolium x corymbosum ‘Northcountry’ have another half-high growing nearby, such as ‘Northblue.’

The most critical aspect of successfully growing blueberries is siting and soil preparation. A garden area where rhododendrons and azaleas are thriving is a site where blueberries will thrive, too. Blueberries like a sunny site with moist, porous, acidic soil and an ideal pH between 4.5 and 5.0. Plan ahead, test your soil, and amend it according to recommendations in the early fall for spring planting. Generally, sulfur is added in the form of iron or ammonium sulfate (not aluminum sulfate, which is toxic to blueberries), and it takes time in warmer weather to work.

Due to the exacting soil requirements, some gardeners opt to build raised bed areas for blueberries. Some newer cultivars, such as the Bushel and Berry® series, have been developed specifically for containers. These are useful in small or patio gardens and where amending the soil is problematic.

Find two-year-old potted plants or bare-root plants. Amend the planting hole with ½ peat moss, which is acidic and provides porosity for better water retention. Mulch new plantings with four inches of hardwood bark mulch or aged sawdust. Do not use mushroom manure as it is too alkaline. Laying soaker hoses under the mulch is useful for easy and adequate watering. Blueberries have shallow root systems and are sensitive to inconsistent soil moisture. They need at least one inch of water per week. A soaker hose will also help reduce the incidence of diseases such as anthracnose fruit rot, botrytis blight and fruit rot, and leaf rust.

Patience is rewarded with blueberries. Wait a few years for a harvest; this shrub may produce strongly for up to 50 years. Remove all flowers for the first two years and up to half the third year. The focus of the plant’s energy will then be turned to cane development. The attractive white flowers are bell-shaped and have a narrow opening. They are pollinated by many different species of bees, most successfully by species that “buzz-pollinate.”

Fertilize yearly with an all-purpose fertilizer meant for acid-loving plants. Keep the mulch at 4 inches. Pruning is necessary to produce a vigorous plant as it matures. Once mature, pruning also invigorates the plant by forcing new growth to replace the older less-productive canes. The best time to prune is at the end of the dormant season, usually in March. Read Pruning Blueberries in Home Fruit Plantings for more detailed information on pruning

It must be noted that independent from the fruit, blueberries are worth growing because they are beautiful. The fall foliage color is gorgeous, from orange-red to striking crimson red and even deep, rich burgundy. However, due to their soil requirements, they are usually not a shrub for the mixed border.

A mature highbush plant produces six to ten pounds/pints of blueberries. Berries picked early will be tart and red and will not ripen off the plant. Wait to harvest until the berries are fully ripe. Blueberries turn blue three to four days before they are at their sweetest and most flavorful. Be aware that birds love this fruit, and your entire crop may disappear in a day while you are waiting. Bird netting is helpful as a barrier to discourage non-human harvesters.

Blueberries in the Kitchen

There are many ways to use blueberries in the kitchen. Start your day with blueberries on top of yogurt or cold cereal, in a smoothie, or as an ingredient in pancakes. Have a peanut butter and blueberry jam sandwich for lunch. Elevate a dinner salad by adding fresh or dried blueberries. End the day with a dessert of blueberry pie or crisp. Blueberry pairs well with many fruits, such as strawberries, rhubarb, and peaches.

This berry is not only sweet and delicious; it is a powerhouse of health, containing vitamins A, C, and K. It is an excellent source of fiber and manganese. Blueberries have perhaps the highest level of antioxidants of any fruit.

Before any food preparation, clean countertops and utensils. Wash your hands with soap and warm water.

Harvest berries in the morning after the dew has dried and before the heat of the day softens the fruit. In a colander, rinse the berries under cold running water but do not soak them.

To prolong the use of blueberries after the harvest, my favorite preserving method is to freeze them using the tray or quick-frozen method. After washing the berries, dry them on a clean towel or paper towel. Place dry blueberries in a single layer on a tray and place in the freezer. Once frozen, remove and quickly place the frozen berries in hard-sided freezer jars or freezer-quality plastic bags. Double bag for better quality.  I always measure the berries before putting them into the bags, the amounts based on the recipes that will be used—usually 2 cups per quart bag. Label the bag with the contents, amount, and date. Frozen this way, the berries are pourable from the freezer. Do not thaw before using in recipes.

In addition to freezing, blueberries can be preserved through canning in boiling water or an atmospheric steam canner. Spiced blueberry jam, blueberry jelly, blueberry syrup, and blueberry pie filling are among the possibilities to put up for the winter. They can also be preserved by drying. Dried blueberries pack a nice punch of intense flavor, eaten on their own or added to trail mix or baked goods. Go to the National Center for Home Food Preservation as the research-based source for safe processes and delicious recipes. Or review Let’s Preserve: Blueberries from our very own food scientists at Penn State.

The following recipe for berry crisp is from Iowa State University. Try it with blueberries alone or in combination with strawberries or raspberries.

Berry Crisp

Serves 8, Serving Size: ½ cup

Ingredients

• 4 cups berries (fresh or frozen)
• ⅓ cup plus 1 tablespoon white or whole wheat flour
• ½ cup oats (old-fashioned or quick cooking)
• ⅓ cup brown sugar
• ½ teaspoon cinnamon
• ¼ teaspoon salt
• ¼ cup butter or margarine, cold
• ¼ cup chopped nuts (optional)

Instructions

1. Preheat oven to 375°F.
2. Thaw berries if frozen. Do not drain.
3. Mix berries with 1 tablespoon flour.
4. Grease or spray with nonstick cooking spray the bottom of an 8″ round or square pan.
5. Spread berries over the bottom of the pan.
6. Stir together the flour, oats, brown sugar, cinnamon, and salt. Incorporate the butter or margarine into the flour mixture. Use a fork or your hands to break the butter down into pea-size pieces while pressing it into the flour mixture. It will be easier to spread on the fruit with smaller chunks. Add nuts, if desired.
7. Sprinkle the flour mixture evenly over the fruit.
8. Bake uncovered for about 25 minutes or until the topping is golden and the fruit is bubbly.