How to Grow Blueberries
Sweet, juicy blueberries grow well where other fruit may not flourish, and they provide a delicious change for your jams, pies and cakes.
Blueberries are a tasty and ornamental fruit which deserve to be more widely grown than they are at present. They thrive on rather poor ground, where other berries would not do well, so they are an excellent choice if your garden is on light, acid, sandy. Blueberries grow in clusters on bushy shrubs, which have a brilliant autumn leaf colour. The small, white, bell-shaped flowers, which smell as sweet as cowslips, appear in mid-spring. They open in succession over a period of several weeks, which helps to diminish damage from frost.
The blueberry most suitable to the home fruit grower is the North American high-bush type (Vaccinium corymbosum), which grows to about 1.8 m (6’) tall, and a few specialist fruit nurseries now offer bushes. However, there are a number of other, harder-to-come-by, edible species of the Vaccinium genus, as well as a number with sour fruits such as the cowberry and the cranberry. The low-bush blueberry (V. angusifolium) produces small, very sweet fruits, and it will tolerate quite cold climates. Its height is about 30 cm (1’). By contrast, the rabbit-eye blueberry (V. asliei) grows freely in sub-tropical areas. The European wild bilberry (V. myrtillus), also called blaeberry, huckleberry or whortleberry, is a close relative of the blueberry; the fruits are small and produced singly, making them harder to pick than the cluster of blueberries.
When choosing a site for your blueberries, consider first if you have had success growing, or if they thrive in your area. Blueberries need similar conditions, and they should grow well where rhododendrons grow. The ideal site is on flat or gently sloping land with an open aspect and free air circulation, although somewhat sheltered from strong winds. Keep in mind that blueberries need a period of winter cold to crop successfully, so they must be grown in sites where frosts occur. Moorland or heath, not usually suitable for cultivation, are excellent sites.
You should never grow blueberries with other fruit, and do not use the same fruit cage. Blueberries will not tolerate the lime and manure which other fruit must have.
If your soil is not acid, do not attempt blueberries, as you will never get a good crop. A soil test should give a pH of 4 to 5.5. The best soil is light sand, high in peat content, moisture-retentive and well drained.
If you are incorporating a tract of heathland into your garden for the first time, it is a good idea to hire a cultivator to do the heaviest work. This will also help to turn in and bury heavy growths of heather and gorse, which will then create an ideal rooting medium. The warm, dry summer months are the best time to do this preparation. Clear the site thoroughly and completely of, especially perennial ones, as the bushes will be down for at least 30 years.
Plant blueberries any time in autumn or winter, spaced 1.8 x 1.8 m (6 x 6’). Although a single bush will form fruit, your crops will be increased if you plant two or more varieties together; you can expect 2.5-4.5 kg (5-10 lb) fruit per bush, picked over a period of eight to ten weeks. Buy healthy two-year-old bushes, which will be about 30 cm (1’) high. Prepare the soil at least a month in advance of planting. If your soil lacks, spread sphagnum peat 7.5 cm (3”) deep over the area to be planted, and mix it in while digging. At the same time, dress the soil with rotted garden or manure at about 51 kg per sq m (12 lb per sq yd).
To plant, dig a hole big enough to contain the natural spread of the roots, and place the plant in it to the same depth as its nursery planting. Crumble the soil back over the roots until the hole is filled, and then mulch around the bush with sawdust 10 or 13 cm (4 or 5”) thick. A 30 g (1 oz) application of general compound fertilizer sprinkled around each bush before mulching will be useful. Staking is not required. No pruning after planting is needed, but if the plants attempt to flower in spring, the flowers should be removed. Blueberries make a slow start, but once established they are long-lived, fruiting for at least 30 years.
Care and cultivation for blueberries is similar to other bush fruits, although they require far less care than many other fruits. If the soil around the plants is heavily mulched every spring with peat or sawdust, watering will be necessary only in hot, dry summers, andwill be minimal. If weeds do appear, they are likely to be perennial, so destroy them immediately and completely. Keep a watch for and remove any blackberry which may appear; birds are the culprits who drop them near the bushes.
Feeding the plants and mulching the soil is important in caring for blueberries. In spring, mulch with a 10 cm (4”) deep layer of sawdust or peat to help retain moisture and stimulate growth. Extra nitrogen will be needed if you have used sawdust. Spread over the sawdust 45 g (I5 oz) sulphate of ammonia or 60 g (2 oz) of dried blood, but use half these quantities where peat is the mulch. Add 30 g (1 oz) of sulphate of potash at the same time. In mid-summer, a further application of the nitrogenous manures may be needed if the soil is particularly poor.
Growth of blueberries takes place in two stages, and it is important to recognize these. First, sideshoots grow from below the flower clusters which formed the previous year. These cease to grow temporarily in early summer, and then resume growth to form flower buds. The second stage of growth begins in mid-summer, when new shoots thrust from the woody crown at ground level; by late autumn these may be 1.8 m (6’) high, with the top 25 cm (10”) covered with potential fruiting buds. Fruit is carried only on the previous year’s shoots, either the new, long growths from the ground, or the sideshoots from the growth completed the year before. Blueberries require some pruning, but it should not begin in earnest until the third winter after planting, when the original branches of the young bush have become dry and twiggy.
Each winter, starting with the third one, cut out the oldest stems which have borne two crops, that is, all the stems which have branches that have completed fruiting. Cut them back to the base, or to a strong, low sideshoot if there is one. This will encourage strong new growth and heavy cropping. Also re-move straggling shoots close to the ground and if there are many new shoots from the base, thin them out a little to get some space and air into the bush. Prune moderately and by about the same amount each year if possible. The removal of too much growth can shock the bush into producing a lot of strong new shoots at the expense of fruit and vice versa. If the summer was dull and cold, it may also be necessary to prune back any green soft growth from the tip. Cut until you reach hard brown wood. You will be able to harvest your first small crop of blueberries the second summer after planting, although the maximum cropping potential of 4.5 k(10 lb) per bush will not be reached for another two to six years. Pick the clusters, starting in mid-summer, when they are firm and very dark blue. You should manage four or five pickings in a season, extending into early autumn. Roll the berries off with your thumb and forefinger, dropping the stalks at the same time. When picking has finished, clear out any weeds and debris on the ground, and renew the mulch if necessary.
Blueberries make a delicious dessert eaten fresh with sugar and cream, or you can use them in cakes, biscuits or tarts. Blueberry jam is superb, and they are an excellent fruit for canning or freezing.