How to Grow Blueberries
Blueberries can even find a place in small gardens. Throughout several weeks a year, they develop a variety of aromatic and healthy fruits. Even the bell-like blossom and the autumn leaves are very decorative. In the garden mainly varieties of highbush blueberries are grown, rarely wild blueberries. For the significantly smaller forest blueberries the conditions in the home garden are usually not ideal.
Commercial, highbush blueberries from the family of heather plants descend from the American blueberry. They are a subshrub and reach a height up to 200 cm. From May the blossoms and from July to September the delicious fruits appear.
In comparison with the domestic forest blueberry, the northern highbush blueberry develops more and bigger fruits, which ripen timely staggered. The flavour of many species is not inferior to their wildly growing relatives. The typical blue mouth after the consumption of forest blueberries fails to appear with the cultivars.
Planting in the garden
Blueberries are mainly planted in the garden. Some species are also very suitable for a tub planting. Wild blueberries find optimal conditions in the garden only in rare cases, that´s why almost exclusively cultivars are grown. Ideally, at purchase you decide upon a 2-3 years container plants which already have several side shoots and are well-rooted. Planting is possible in early spring and autumn.
Even if blueberries are undemanding, they need regular care. Firstly, an appropriate location has to be determined. In contrast to wild blueberries, which grow in semi-shady areas, cultivated species prefer a wind-protected, fully sunny but not too hot location. Having found the right location, the soil has to be prepared.
Preparing the soil
The blueberries have very high requirements concerning the soil because these plants belong to the so-called bog plants. Accordingly the pH-value should be low, therefore acid and between 4 and 4, 5. Moreover, it should be evenly wet, humus-rich, lime-free, well-aerated as well as sandy to marshy.
A high percentage of humus keeps the soil wet, which the blueberry benefits from. In contrast, waterlogged and condensed soils have to be avoided. If the soil is not acid enough, it is recommendable to replace it completely. For this purpose, you can dig a 40-50 cm deep and 100 cm wide hole and fill it with peat or a special rhododendron or azalea substrate. This substrate has exactly the features that the blueberry requires.
If you want to forgo peat for ecological reasons, you can acidify the soil with the addition of bark humus, sawdust, leaf mould, bark mould as well as fir and spruce needle litter.
Most species of the highbush blueberry are self-fertile, this means that also single plants bear fruits. However, it makes sense to plant at least two different species because the fruit yield is significantly higher. If you chose two species with different ripening seasons, you can enjoy the delicious fruits from July throughout to September. Blueberries can be planted in different ways.
In order to prevent an excessive growth of weeds, it is recommendable to cover the root area after planting with rotten plant material such as wood chips, fir litter, fir cutting or bark mulch. Such a cover is also a good winter protection.
You should forgo chemical herbicides because the blueberry roots are particularly sensitive to any kind of herbicides. Companion plants with similar requirements such as cranberries, grape hyacinths, small rhododendrons, azaleas, heathers or the Japanese iris make the blueberry look particularly adorningly.
Planting in the bucket
A good alternative to planting in the garden is planting in a bucket such as on a balcony facing the sun or on a terrace. Keeping them in a bucket is particularly beneficial for species that react sensitively to windy locations. Moreover, rather small species should be chosen such as “Sunshine Blue” or “Northsky”. The advantage of keeping the plants in a bucket is that the acid content of the soil can be controlled better than in a bed.
The respective plant vessel should be wide enough and have sufficient drainage holes. Recommendable is a capacity of at least 50 litres. Concerning the substrate, the same conditions apply as for planting in the garden.
The bucket is filled with acid and loose substrate up to few centimetres under the rim of the pot and the plant can be put and finally it is watered abundantly. The bucket plants should hibernate in a frost-free but cold winter habitat
Replanting old blueberries
Highbush blueberries can remain in the same location for up to 30 years with an appropriate fertilisation and care. However, if it should be necessary to replant the blueberry, it becomes more difficult the older the plant is. The best time is after harvest in late summer or autumn if no extensive dry period can be expected any more. For this purpose, you ideally chose a rainy day.
The replanting in autumn has the advantage that the plants root better in the new location and therefore they possibly bear fruits in the following spring. Obviously, it can be replanted in early spring before the beginning of the shoot. But in this case the plants usually bear fruits only in the upcoming year.
Before replanting, the soil in the new location has to be prepared appropriately and lined with foil, if required. The plant hole, which should be significantly bigger than for a newplanting, is dug out. Digging out the blueberry, you have to consider digging out the root area with its flat-spreading roots in a big radius in order to damage or injure it as least as possible.
The plant pit is filled with appropriate substrate and the blueberry is planted. For bigger plants pruning before planting is recommendable to make the growth easier for the plant. At regular intervals, the blueberries must also be repotted in vessels just like in the garden and the size of the pot must be adjusted to the size of the shrubs. In too small plant vessels deficiency symptoms such as stunted growth can quickly occur.
After the blueberries were planted, you have to focus on the additional care. Only if location, conditions of the soil and the subsequent care meet the requirements of this plant, they can develop well and produce a high yield of fruits.
Accordingly, bucket plants must be watered more frequently, because the substrate dries up much more quickly and more extensively in the pot than in the garden. Especially during the fruit setting and the harvest, the plants should be controlled regularly and watered appropriately.
The harvest time of blueberries in the garden begins in the middle of July and ends approximately in September. In contrast to wild blueberries that ripens at the same time, the harvest of highbush blueberries extends into several weeks. The fruits continuously after-ripen in stages. In general, blueberries should only be harvested if they are deep blue because only then they have acquired their complete aroma. The longer they remain in the shrub, the sweeter they taste.
Fruits that are harvested in unripe condition will not after-ripen any more. In the year of the planting, the yield is not very high yet. The highest yield can mostly be achieved after about 6 years. The so-called blueberry comb, which is often used for the harvest of forest blueberries, is only suitable for highbush blueberries to a limited extent because due to the delayed ripeness the cultivated species mostly bear unripe and completely ripe fruits next to each other. Therefore, the harvest by hand provides the best quality.