Lowbush blueberry (Vaccinium angustifolium) is a blueberry shrub native to Canada. Its fruits, or blueberries, are a very important edible berry and are normally packaged frozen. They are made into jams, preserves, syrups, ice cream, pies, and juices. Lowbush blueberry attracts honey bees and other pollinators.
I. Appearance and CharacteristicsÂ
Vaccinium angustifolium, commonly known as the wild lowbush blueberry, is a species of blueberry native to eastern and central Canada (from Manitoba to Newfoundland) and the northeastern United States, growing as far south as the Great Smoky Mountains and west to the Great Lakes region. Vaccinium angustifolium is the most common species of the commercially used wild blueberries and is considered the “low sweet” berry.
The species epithet angustifolium is a combination of the Latin words angustum meaning ‘narrow’, and folium meaning ‘leaf’.
Vaccinium angustifolium is a low spreading deciduous shrub growing 5 to 60 cm (2 to 24 in) tall. Its rhizomes can lie dormant up to 100 years, and when given the adequate amount of sunlight, soil moisture, and oxygen content they will sprout. The leaves are glossy blue-green in summer, turning a variety of reds in the fall. The leaf shape is broad to elliptical. Buds are brownish red in stem axils. The flowers are white or pink, bell-shaped, 4 to 6 mm (0.16 to 0.24 in) long. The fruit is a small sweet dark blue to black berry, full of antioxidants and flavonoids. This plant grows best in wooded areas, old abandoned farmyards or open areas with well-drained acidic soils. In some areas it produces natural blueberry barrens, where it is practically the only species covering large areas.
Several buds may be on a healthy stem, and each bud can open up and have several blossoms. A blueberry field that has full plant coverage can have as many as 150 million blossoms per acre.
The Vaccinium angustifolium plant is fire-tolerant, and its numbers often increase in an area following a forest fire. Traditionally, blueberry growers burn their fields every few years to eliminate shrubs and fertilize the soil. In Acadian French, a blueberry field is known as a brûlis (from brûlé ‘burnt’) because of that technique, which is still in use.
Vaccinium angustifolium has a two year production cycle. The first year is known as the vegetative year and the second is known as the fruit-bearing year.
In order to be productive each year, most farmers divide their land to have half their crop in the vegetative year while the other half is in the fruit-bearing year.
II. How to Grow and Care
Sunlight
The lowbush blueberry is a full sun plant. Insufficient sunlight affects its flowering and fruiting. When selecting a growing location, try to avoid placing your plants near large trees. The tree crown coverage not only affects light, but also reduces air circulation, making diseases much more likely.
Temperature
The lowbush blueberry has many cultivated species that have a wide adaptability to different temperatures. However, cold temperatures (T < 7 ℃) during dormancy are vital to helping them bloom the following year. The Lowbush Blueberry and the Northern High Blueberry usually need more than 800 to 1000 chill hours in an environment below 7 ℃. The Rabbiteye lowbush blueberry from the south also needs around 350 to 700 hours. It is important to pay attention to cold resistance and chill hours when selecting varieties.
The lowbush blueberry has a fibrous root system with shallow root distribution. Like other Ericaceae species, its roots with symbiotic fungi absorb water and nutrients from the soil. Therefore, the lowbush blueberry is neither drought-resistant nor flood-resistant, and requires careful adjustment of soil moisture.
Watering
Regular watering is needed to grow lowbush blueberry. Since the sandy soil it prefers has low humidity and low water retention, irrigation should be done every two or three days during a hot summer. Deep watering may be required once a week. In total, lowbush blueberry requires the amount of water equivalent to an average precipitation of 2.5 cm per week from germination to defoliation, and then around 4 cm from the beginning of fruit bearing to fruit harvesting. Water supply should be reduced from fall to enable the plant to enter dormancy in time.
Soil
Because the wild blueberries mostly grows on the edges of forests, they are accustomed to the acidic soil formed by dead branches and fallen leaves.Loose, acid soil (pH 3.8-5.5) with a good drainage performance and plenty of humus is best, with the optimum pH value being 4.5. Sandy soil and sandy loam are also preferred.
Soil acidity can be adjusted to cater to the lowbush blueberry. If the pH of your soil is between 5.5 and 7.0, sphagnum peat can be applied at a 10 to 15 cm thickness into the 0 to 150 mm top-layer of soil, before being fully mixed in. Sphagnum peat not only improves soil acidity, but also significantly increases the content of humus. If the pH of your soil is higher than 7.0, a raised ridge bed can be built and filled with soil that has the correct acidity. Back-filling soil should be 20 to 30 cm higher than the ground plane, and all roots must be covered in the soil layer below 0 to 150 mm.
Fertilizing
The lowbush blueberry is a plant that does not demand much fertilizer. However, if you are meeting soil acidity requirements and the leaves are losing their green color, or new shoots are growing extremely slowly, a nitrogen fertilizer should be considered. Ammonium nitrogen is the best kind of nitrogen fertilizer for a lowbush blueberry.
After planting, young plants should be fertilized in early spring and late spring respectively. For adult plants, fertilizer can be applied every fall and winter after flowering. Each plant would benefit from an organic fertilizer or a compound fertilizerÂ
(N%-P2O5%-K2O%=15:15:15).
Excessive fertilization easily damages the lowbush blueberry, and can even kill the whole plant. Forbidden fertilizer types include chlorine-containing fertilizer; nitrate nitrogen fertilizer; calcium-containing fertilizer.
Planting Instructions
Planting requirements for the lowbush blueberry differ between varieties. Ideally, use bag seedlings that are two to three years old when planting a lowbush blueberry, with the diameter of the base of the main stem being more than 5 mm.
If garden centers provide bare-root seedlings, these can be stored in a damp and dark environment before planting to keep them in dormancy. The criterion of “dampness” is that the roots must be kept moist, but not fully saturated. Ideal planting time is usually late winter or early spring, before the plant starts sprouting new buds. Soak the roots of bare-root seedlings in water for 3 or 4 hours before planting.
Two or more plants of different species, with the same florescence, can be planted at the same time. Pollination between different plants can increase the fruit setting rate, as well as the single fruit weight. For species with a larger plant shape, the spacing should be appropriately increased.
If you are planting lowbush blueberry into a pot, place this in a shaded and well-ventilated room for a week, before moving it outdoors and resuming with normal care. If on sloping land, avoid planting in locations where cold air stagnates, so that the plant is protected from frost during flowering. Adequate irrigation should also be carried out after planting. Maintain an organic mulch at a thickness of 5 to 10 cm throughout the year after planting.
A mulch such as broken wood sawdust, peat, pine needles and fallen leaves can help maintain soil acidity. As acidic organic matter degrades every year, the pH value of your soil needs annual monitoring, with adjustments as needed. Once the pH value of the soil is higher than 5.5, the lowbush blueberry roots cannot absorb iron, meaning that the edges of leaves will lose their green color and turn red. Growth will be stunted, and the plant could even die. An acid peat soil mixture, while useful, takes effect slowly. If there are signs of an iron deficiency during the growing season, a chelated iron foliar fertilizer can be sprayed and a sulfur powder can be used to adjust the pH value of the soil.
Pruning
Native Americans regularly burned away trees and shrubs in parts of eastern Maine to stimulate blueberry production. Modern farmers use various methods of burning or mowing to accomplish this. There are several methods growers use to stimulate blueberry production on their land, such as burning the land or using a flail mower, bush hog, lawnmower, etc. to cut the plants off as close to the ground as possible without scalping the land. These procedures are used to promote the spreading of rhizomes under the soil.Â
Some growers use a sickle bar mower in the fall after the crop has been harvested to mow the plants off, leaving roughly 1 to 2 inches of stem so the growers can then burn the remainder of the plants in the spring, using less fuel for the fire.
Farmers then treat their crops with pesticides to control weeds and insects. The fields are then left for new growth to emerge, develop, and flourish for the remainder of the year.
Pollination
During the harvest or fruit bearing year, blueberry growers rent honey bee hives to put in their fields for pollination. These hives are placed in the fields at a density range of anywhere from 1-8 hives per acre. The hives are placed in the fields at 10-20% bloom allowing the bees to have enough forage rather than going elsewhere to forage. Hives are left in blueberry fields for 2 weeks on average, allowing the bees to pollinate the variety of clones in the field, all of which bloom at different times during the two-week period.
Some growers also use bumble bees as well in hopes of maximum pollination. Bumblebees will fly in colder and wetter weather conditions than the honey bee will, and they also pollinate in a different way than the honey bee. Bumblebees can sonicate the flowers, which releases pollen from deep inside the poricidal anthers. This is known as buzz-pollination.
Blueberry growers also rely on many wild bees for pollination, including solitary bees like Andrena carlini and Colletes inaequalis.
III. Uses and BenefitsÂ
- Ornamental uses
Commonly overlooked by commercial growers, lowbush blueberry is hardier and sweeter than the standard highbush blueberries. Also, unlike their relatives, they are easy to grow, bringing attractive, pretty blooms and tasy, edible blueberries to your garden. Growing in the form of low, bushy, and trailing, lowbush blueberry can be mass-planted as part of mixed shrub borders or as a ground cover.
- Culinary uses
You can dry them, can them, or make blueberry jam. You can even infuse them in vinegar for a delicious dressing or marinade.
Blueberries can be dried in a dehydrator set on low for approximately 18 hours or baked in a preheated oven set to the lowest temperature for about three hours, until they are fully dry.
Leave to cool and store in an airtight container.
To make blueberry vinegar, place one part blueberries to two parts vinegar in a glass jar. Smash the berries with a fork, seal with a plastic lid, and give the jar a good shake.
Set in a cool location for a few days, shaking the jar daily. Strain the berries and boil the infused vinegar for about a minute, skimming off any debris that surfaces. Strain one more time and store in a cool dark location.
IV. Harvesting and Storage
The lowbush blueberry fruiting period can last for several weeks. Fruit ripens when its surface turns bluish black. Due to inconsistent ripening of fruits, they should be harvested in batches. Harvest once every 2 or 3 days in full fruit period, and once every 3 or 4 days in both the initial and final fruit period, completing your harvest before the frost.
Gloves (finger sleeves) should be worn when picking fruits to avoid damaging them, which would affect their appearance and storage potential. When picking ripe fruits, gently hold the berries and tweak them clockwise to keep the peel intact. This will also help to prolong their storage period.
To freeze, wash and let the berries dry thoroughly. This is especially important if they may have been sprayed with any pesticides. Next, spread them out in a single layer on a baking sheet and freeze for several hours. When they are completely frozen, you can transfer them to a freezer bag for long term storage. The berries should be kept for one to two years.
