Blueberry Duke. Description of the variety, photo, ripening time, pollinators, ripening time, frost resistance

Characteristic

Duke blueberries (variety description, photos, reviews are presented in the article for a basic introduction to the culture) were obtained in the 70s of the last century in the USA. The variety is suitable for cultivation in the Moscow region, Volga region and central Russia.

Characteristic features of blueberries of the Duke variety:

1. The shrub has fibrous roots that are deepened by 20 cm. The shoots are straight and colored brown-green. More mature shrubs begin to thicken greatly.
2. The plant grows quite quickly, forming a huge amount of shoots.
3. The height of the bush varies within 2 m, width 1.5 m.
4. At the flowering stage, blueberries are covered with delicate white-pink flowers. Flowers are collected in brushes.
5. At the fruiting stage, large berries appear on the bush, which have a round and slightly flattened shape. The average fruit weight reaches approximately 2.5 g.
6. The pulp is characterized by a green and translucent hue, good density and juiciness. It contains a large number of seeds. The edible part is quite aromatic, slightly tart, but sweet. The pulp is covered with a bluish-blue skin, on which there is a smoky coating. The skin is quite durable.

The photo shows blueberry fruits of the Duke variety.

The flowering of the bush begins at the end of May. The ripening of the berries lasts for 56 days.

The variety is considered self-fertile and therefore does not require other pollinators. The productivity indicator is high. The fruits are collected during the last 2 months of summer. However, the harvesting period depends on the climate of the region. The first harvest can be obtained 24 months after the seedling takes root.

Collection and storage of blueberries

The Duke variety can be harvested from the second half of July. They do it manually. Harvesting can take place in 2-3 stages, although the size of the berries will not decrease from the harvesting stage. The variety tolerates transportation well.

Blueberries can be stored at room temperature for 3-4 days, in the refrigerator - up to 1 week. Blueberries are suitable for freezing: they can be stored in the freezer for 12 months. Blueberries are also dried, ground with sugar, and made into jams and preserves.

Preparation of planting material and propagation

It is recommended to buy seedlings in special nurseries or garden centers, where the plant is constantly under strict control. In such establishments, planting material is placed in containers. If the seedling has an open root system, it is not advisable to buy a young blueberry bush. This is due to the fact that the plant may not take root.

For planting in open ground, it is recommended to purchase a seedling that meets the following parameters:

• age should not exceed more than 3 years;
• the bark must be free of defects and the roots must be closed;
• shoots should be elastic, healthy and without damage.

There are several ways to propagate the Duke variety: layering, cuttings and seeds. The latter method is not used too often, since the first harvest will not appear earlier than in 8 years. It is convenient and quick to propagate blueberries vegetatively.

To propagate a plant by cuttings, it is recommended to follow these steps:

1. Lignified shoots that were cut in the autumn need to be sent to a cool place.
2. With the arrival of April, the shoots will need to be divided into parts, the length of which reaches 20 cm. The prepared shoots must be lowered into a composition based on peat and sand at an angle of 45 ℃. Then the planting material must be irrigated with water and covered with a protective film.
3. The cuttings need to be constantly ventilated so that fresh air reaches them. Once every 7 days the soil layer should be moistened.
4. In August, it is necessary to completely remove the protective film. This is necessary so that the rooted cuttings can undergo the hardening procedure.
5. With the arrival of autumn, seedlings need to be planted in a separate bed for growing.
6. After 2 years, the cuttings can be sent to a permanent place.

To propagate blueberries by layering, you will need to bury the shoot into a hole located under the bush. First, you will need to add a sand-based mixture with sawdust and peat to the soil layer.

The branches must be secured with staples and covered with a protective film. The procedure for separating cuttings from the bush must be carried out next year in the spring. If the rooting process takes too long, the separation procedure must be postponed to a later date.

History of creation

Duke was bred in 1972 by a group of American breeders consisting of G. Galletta, N. Vorsa, G. Jelenkovic, led by AD Draper (from USDA-ARS). Breeding took place in Beltsville, Maryland, as part of the US Department of Agriculture (USDA) Highbush Blueberry Breeding Program. As a result of cross-pollination of numbered varieties G-100 (Ivanhoe X Earliblue) X 192−8 (E-30 X E-11), seedlings of a new variety were obtained, which subsequently showed excellent quality, berry size, yield and quite early ripening. After many years of observation, the new seedlings went on public sale in 1987.

Preparing the soil and planting site

Blueberries Duke (variety description, photos, reviews will help gardeners prepare the soil and planting site correctly) needs light and thoroughly drained soil. Acidity should be within 5.5 pH. The best soil is peat or sand.

If the acidity level of the area is low, it will need to be raised. You will need to dilute 30 g of any acid in a bucket of water and pour the mixture over the soil. It should not be poured over the entire territory, but only into the hole for the seedling.

The area should be spacious so that the bush can grow unhindered. Blueberries like areas with plenty of shade, but the fruits will be sour in taste and small in size.

The location for planting the bush should be sunny, in a closed area without wind or drafts. You should not grow the plant near large fruit trees. They draw out nutrients and moisture that are necessary for the development of the seedling.

To prepare the hole and soil for planting a seedling, you must adhere to the following recommendations:

1. If there is underground water nearby, blueberries must be planted on an artificial hill.
2. The pit will need to be filled with a light, acidic and loose earthen layer. Garden soil will not work. The main components that should be included in the substrate are peat and sand.
3. The pit must be 50x50 cm and 60 cm deep. You will need to place a drainage made of wood or pieces of bark on the base. Crushed stone is not suitable for drainage, as it can reduce the acidity of the soil.
4. If the soil is too dense, the size of the hole should be 90x90 cm. This is due to the fact that the roots of the bush are superficial and grow to the sides.
5. For mycorrhiza to appear, an increased level of acidity is required. When the pH is above 4.5, overripe pine needles, pine bark and pine sawdust should be added to the soil in a ratio of 2:1:1.

Blueberries will not grow in the place where vegetable crops were. For planting, it is recommended to choose an area where there are wild herbs with a lack of fresh organic matter in the soil. Neighborhood with raspberries, currants and gooseberries is not allowed. The best neighbors will be hydrangeas, azaleas and rhododendrons.

Reviews

Let’s find out what gardeners say about this fruit and berry crop.

I planted blueberries at the dacha as an experiment: I was wondering if these garden varieties were so productive. The choice fell on the Duke variety - it has been on the market for a long time, it is praised in foreign forums. Blueberries began to bear fruit in the second year: the first berries do not have a pronounced taste, but then they gain sweetness.

I liked the variety: I think the harvests will become even more abundant in the future. The plant is not too picky when it comes to care, but the planting site must be chosen carefully. Prevention is required to avoid fungus. And so I have no complaints.

Lyubov Vasilievna, Penza:

A neighbor in the country gave me a Duke blueberry seedling. I planted it, but I didn’t really think that it would take root, and even bear fruit. But the plant took root - probably the site was chosen well. The second year we already tried the berries, but there were not enough. Now the harvests are much richer, since it is already the eighth year since planting.

I like the taste of blueberries, and the berry is also healthy. For us, pensioners, this is important.

Landing algorithm

Blueberry Duke (variety description, photos, reviews will tell novice gardeners how to properly plant a bush outside and at what time period) requires planting in the autumn or spring.

In the southern regions, where cooling occurs a little later, it is best to carry out autumn planting, which should begin approximately 45 days before the arrival of the first frost. This is necessary so that the seedling grows young roots, receives nutrients from the soil layer and prepares for winter.

When planting a plant in the spring, the snow should completely melt outside and the soil should warm up to a temperature of +5 ℃. It is necessary to plant a young bush before sap flow begins. Summer planting of blueberries is not carried out, because due to the heat the seedling will not adapt well to the new conditions.

The timing of planting is influenced by the climate of the region in which blueberries are grown:

• in the southern regions it is permissible to plant in March;
• in the middle zone, all planting work is recommended to be carried out in April;
• in the Urals and Siberia the procedure is carried out in May.

If the seedlings have not matured until autumn, planting work is best done in the spring. To do this, you will need to prepare the soil at the beginning of the autumn season by measuring the acidity of the soil and digging a hole in the soil. You will need to add substances that contain nitrogen to the soil. The amount of fertilizer will depend on the amount of nitrogen contained in the soil.

Planting seedlings can be done in 2 ways:

1. Kustov. Holes need to be dug at a distance of 1.5 m from each other. The diameter of the seat should reach 80 cm and the depth 40 cm.
2. Trench. If you need to plant several bushes, the procedure must be carried out in rows to a depth of 40 cm. The distance between seedlings should be 50 cm, between planting lines no more than 2.5 m.

The algorithm for planting blueberry seedlings is based on the following steps:

1. The base of the seat or trench must be covered with peat, which must be mixed with sawdust or pine bark and pine litter.
2. Next, you will need to add acidified water to the soil layer. The acid can be malic or acetic (100 g of liquid is needed per 10 liters of water), oxalic or citric (5 g per 10 liters of water).
3. Before planting, the roots of the seedling must be immersed in the solution to stimulate root formation for approximately 2 hours.
4. The lower part of the root needs to be divided into 6 parts, spreading each in different directions.
5. The prepared bush must be lowered into the hole and sprinkled with soil, deepening the root collar by about 5 cm.
6. The soil layer must be irrigated abundantly with water. When the liquid is completely absorbed, the surface of the earth needs to be mulched. The mulch layer should be at least 10 cm.
7. If planting occurs in the spring, the seedling needs to be shortened by ¼. Due to this, the plant will bush better.

Preparing for winter

Duke blueberries overwinter very unpredictably. The bush can easily withstand frosts down to -34 degrees, but at the same time freeze out in light frosts. Therefore, if there is a risk of frost, it is important to water the plant abundantly during the day, doing moisture-charging watering.

This depends on the degree of soil moisture and the strength of the shoots. That is why, when planting, it is important to deepen the root collar so that if wintering is unsuccessful, the bush does not die completely.

Before wintering, weak branches should be cut off, strong branches should be bent to the ground and tied up. The bushes are covered with agrotextile on top.

Care

Duke blueberries can bear fruit for 20 years with careful and regular care, which is based on timely watering, pruning and fertilizing. A description of the variety with photos and reviews will help you properly care for the shrub.

Spraying, watering

The plant loves moisture, so the taste of the fruit and yield depend on the quality of irrigation. The bush needs to be watered 4 times a month with a bucket of settled water. Irrigation must be increased when budding and berry formation occur.

Watering is carried out in the following ways:

• rainy;
• drip irrigation;
• under the root.

In order not to harm the bush, watering in the form of rain should be carried out in the morning or after sunset.

Top dressing

Duke blueberries should not be fertilized with organic matter, since chicken droppings and manure saturate the soil with alkali and can lead to the death of the bush.

There is no need to fertilize in the first year after planting.

After 12 months, it is necessary to fertilize, following the following tips:

• ammonium nitrate or ammonium sulfate should be applied in the spring;
• potassium salt is added after harvesting;
• superphosphate should be used at the moment of fruit formation.

Based on the appearance of the bush, it is possible to identify a deficiency of microelements in the plant:

1. Reduced yield, stunted development and yellow foliage indicate that the plant lacks nitrogen.
2. A small amount of phosphorus is expressed by turning the foliage brown.
3. Dying and darkening of the shoot tip indicates potassium deficiency.
4. The foliage takes on a yellow-white hue and becomes discolored over time if there is a deficiency of sulfur in the soil.

Dry fertilizers should be scattered over the area of ​​the tree trunk circle when the soil is abundantly watered.

Transfer

The best option for transplantation in the northern regions is spring. This is due to the fact that frosts begin too early in the autumn and the plant may not have time to take root. The most favorable time is considered to be April or early May. The soil will be well moistened and sufficiently warmed.

It is advisable to carry out autumn replanting in September, so that there is enough time left before the onset of cold weather. The plant is able to adapt to a new place in a few months, take root, and grow to its full height in the spring.

To transplant an adult bush to a new area, you must complete the following steps:

1. It is necessary to prepare a landing hole. It is important to carry out planting as soon as possible so that the root system of the plant does not begin to wither under the rays of the sun. It is recommended to carry out work in the evening after sunset. The depth and diameter of the hole should be 50x50 cm.
2. For good survival of the bush, the soil should be adjusted by placing a top layer of peat, sand and pine litter in a ratio of 5:1:2 into the hole. The composition should be added to the hole after planting.
3. The soil can be fertilized with mineral components. For 1 planting you will need 40 g of ammonium sulfate, 100 g of superphosphate and 30 g of potassium sulfate.
4. An adult bush needs to be dug up from all sides and uprooted with a shovel. The procedure should be carried out with extreme caution so as not to damage the root system.
5. The shrub along with the earthen ball should be moved, placed in a new planting hole and sprinkled with soil mixture.

At the end, the planting must be thoroughly watered with 10 liters of water and the tree trunk circle mulched. Then you will need to follow the rules of care: weed the soil, regularly water and take preventive measures to protect against pests and diseases.

Trimming, tying, pinching

There is no need to prune the bush during the first 5 years.

After blueberries grow, pruning should be done:

1. Young growth, thickening shoots, dry and deformed branches.
2. Large annual stems, leaving the largest ones in the amount of 5 pieces. Thanks to this, a spreading and straight bush will be formed, which will be ventilated and saturated with sunlight from all sides.
3. A bush over 10 years old needs to undergo anti-aging pruning, removing up to 20% of the stems at the root every year.

Temperature and humidity

The plant is resistant to cold weather conditions and can withstand down to -30 ℃. Adult crops do not require shelter, unlike young ones, which should be insulated in the first 2 years of life.

Preparation for winter should be carried out in this way:

1. The tree trunk circle must be covered with peat or pine needles 30 days before the onset of frost.
2. Arches should be installed above the plant, which are covered with burlap.
3. Then the structure will need to be covered with spruce branches, dry leaves and sprinkled generously with snow. To prevent the plant from rotting, air must get inside.
4. The shelter should be removed after the arrival of warm weather. Frozen branches need to be trimmed back to healthy tissue.

The plant needs a lot of liquid, so the desired level of humidity should be constantly maintained.

Description of the Duke blueberry variety

When describing the Duke variety, first of all it should be mentioned that this crop is characterized by strong growth and high frost resistance. On average, the height of an adult specimen can be two meters. In this case, the shoots grow vertically, and practically no lateral branches are formed (Figure 1).

In addition, the variety is characterized by increased resistance to cold. Thanks to this, in winter, not only are young shoots and buds not damaged, but also the root system, which lies close to the surface.

Note: This feature allows Duke blueberries to be grown even in regions with cold climates, but the plants should still be covered for the winter to provide additional protection from frost.

The tall and frost-resistant Duke blueberry is also characterized by high and stable fruiting. The ripening of the berries begins at the end of July, and the fruits are large in size: the diameter of individual berries can reach 2 cm. But a much more pleasant feature of the variety is the ease of picking the berries: they are easily torn from the branches, and their pulp is quite dense, so the fruits are not crushed during collection time. On average, up to 6 kg of berries can be harvested from one bush per season, and if the crop has been properly cared for, the harvest volume can reach 8 kg from one bush. Moreover, even ripe fruits are excellent for storage and transportation, thanks to their thick skin, which preserves the integrity of the berries.

Figure 1. External features of the Duke variety

The only drawback of this variety is the need for constant care. First of all, this concerns pruning. Since the crop is characterized by strong and rapid growth of shoots, formative pruning of the bush must be carried out annually. Without this procedure, the crown of the bush will become too thick, which will lead to crushing of the fruits and reduced yield. In addition, you need to choose the right site for planting the crop, since in soils with high humidity the plant not only takes root poorly and bears little fruit, but may even die from root rot or fungal diseases.

Possible diseases and pests, ways to get rid of them

Blueberry Duke (variety description, photos, reviews will help novice growers properly care for the plant during illness and pest invasion) does not like thickening of the crown. Without trimming the stems, a fungal outbreak may develop.

Main diseases of Duke blueberry and their treatment:

1. Anthracnose. Signs of the disease are the presence of dark spots on shoots, foliage and fruits. It should be treated with Fitosporin-M or fungicides. Preventive measures are limited to leaf removal.
2. Cancer. Cracks and red ulcers form on the bark. Treatment is considered to be thinning pruning. Prevention of the disease is the use of Azofos.
3. Gray rot. Manifests itself in the form of gray spots of mycelium and rotting. For treatment, you will need nitrogen preparations, which must be given strictly according to the norm. Thinning the bush will also help. Prevention is considered to be treating the plant with iron sulfate in early spring, and at the end of May with Bordeaux mixture.

There are pests that rarely attack the plant:

1. Leaf roller. Insect contact with a plant leads to damage to buds, flowers and curling of leaves. The crop should be treated with insecticides. As a preventative measure, it is necessary to remove fallen leaves and carrion.
2. Chafer. If the foliage turns yellow, it means that insect larvae are gnawing on the roots. To combat the beetle, you need “Antikrushch” and preventive measures in the form of shaking branches and light traps.
3. Aphid. Damaged leaves should be treated with a solution of soda or soap. For prevention, it will be enough to treat the bush with an ant repellent.

Peculiarities

Since Duke blueberries are unpretentious in care and have a high yield, the variety is often cultivated on an industrial scale.

To grow a fruit bush in a summer cottage, it is recommended to familiarize yourself with all its advantages and disadvantages in advance:

With proper cultivation of Duke blueberries in a summer cottage, the bush will regularly produce high-quality and tasty fruits. A description of the variety with photos and reviews will help you correctly follow all agrotechnical rules that relate to growing garden crops in open ground.

Strengths of the variety

• Large berries and good stable yield, a large percentage of one-dimensional fruits.
• Late flowering period, protecting flowers from spring frosts.
• Friendly and very early ripening of fruits, the ability to carry out mass sampling. Thanks to this, Duke is of particular interest to the fresh berry market, allowing it to sell a larger quantity of the crop at a high price.
• Strong growth energy, moderate branching of lateral shoots.
• Good transportability and keeping quality of berries.
• The versatility of fruit use.
• Sweet, juicy berries with aromatic pulp and a rich aftertaste.
• The hardiness of the variety and adaptation to various growing conditions both in the north and in the south.
• Resistance to major blueberry diseases.
• Possibility of using the plant for decorative purposes.