Blueberries

• Blueberries – easy to grow, manage and harvest.
• Productive over many years.
• Great container plants in ericaceous soil.

Blueberries are perennial flowering shrubs with indigo to purple coloured berries located in the taxonomy within the genus Vaccinium. Species in the section Cyanococcus are the most common fruits sold as “blueberries” and these are native to North America. There are a number of species grown only for the fruit and there is still plenty of collection of the berries in the wild. Indeed many animals such as bears rely on them as winter food prior to hibernation. The European Bilberry (Vaccinium myrtillus L.) is often found in jams, various dairy desserts and cake toppings.

North America (USA and Canada) has the following species:-  highbush (V. corymbosum L.), lowbush (V. angustifolium Ait.), and rabbit-eye types (V. ashei). The latter species is native to the Gulf Coast states such as Northern Florida and Georgia but will grow equally well in other parts of the South-Eastern USA.

The Southern highbush is a new category of commercial blueberry developed mainly for the southern United States. It has a relatively early flowering date, a shorter ripening period than northern highbush, and has lower chill hours and adaptability to the warmer southern climates.

A number of varieties are worth trying and the harvesting season is extended with different bushes. The season can start with ‘Duke‘ followed by ‘Bluecrop‘ and ending with ‘Brigitta Blue‘. Other varieties with good flavour include ‘Patriot‘, ‘Polaris‘, ‘Spartan‘, ‘Bluegold‘ and ‘Ozarkblue‘. One variety, a semi-evergreen, self-fertile and compact growing type called ‘Sunshine Blue’ is ideal for small pots, patios or courtyards.

Cultivation

Possessing a couple of blueberry bushes is an incredibly valuable addition to the fruit crop as they regularly produce fruit over many seasons with little effort involved. They are generally purchased as young bushes for planting into large tubs or open ground but their soil requirements are specific. 

Most plants enjoy growing in a pot of at least 2 litres or in ground which is acidic, peaty, sandy and similar to open heathland. It is best to plant any young bushes after the first frosts although they are extremely hardy and will endure severe weather. The soil must be free draining and not above pH6. Testing kits are used to help identify whether the soil is acidic enough although ericaceous compost will easily do the trick and reduce the alkalinity of ordinary limey soil.

Plants in containers will last 10 years before they have to be repotted in ones of about 60 litres because of their extensive root systems.

All plants need constant and regular watering – rainwater is ideal to maintain pH. It is quite evident when they are dry because the leaves turn a red colour. Full sun is required for as much of the day as possible although the varieties I grow appear to thrive in partial shade which suggests they are not as needy.

Feed the young plants with rhododendron fertiliser or seaweed extract. Watering is maintained when berries appear following the dull white flowers. The fruit usually sets in mid-summer. Trickle irrigation is helpful but constant watering is needed with some fresh compost added to fill in gaps especially with container grown plants.

Most young bushes take two years to mature. The overall length of time is three to four years.

Continued Care And Pruning

Most plants bought from the garden centre or nursery are usually about two weeks old, so will not need pruning on planting.

Old stems should be cut away as the bush ages and to ground level with a secateurs in winter/spring. This encourages new growth and removes stems that can develop disease. Trim any dead or damaged branches as well as those hitting the ground. When the growing season is complete, all varieties lose their leaves but give a fine colour display during autumn.

Blueberries crop on the tips of one-year-old growth, and then start to send out small side branches on older wood which also flower and fruit.

Fruit Harvesting

The fruits form from June to September where they turn from pale green to a deep dark blue with hint of purple. Pick the fruit otherwise the birds, especially blackbirds will take them. I cover the bushes with garden mesh and netting to hide the fruit. None will ripen at the same time but do not pick when any pink colour remains as they taste acidic and sour. Fruit should remain on the bush after ripening to encourage further sweetening and flavour development.

Blueberry Propagation

Blueberries grown for fruit can be difficult to strike from cuttings. The soft young shoots and any dormant ones in winter which are then taken in spring can be used, as can hardwood cuttings. Semi-ripe shoots which are ones that have not hardened at the tips are taken in late June to early July and these are the easiest for getting to strike. Shoots that are taken – usually about 10cm long are cut and the lower leaves removed. the cutting is inserted in a rooting medium and placed ina covered heated propagator. Rooting takes about 6 weeks. Any cuttings that have rooted are then potted up in the following spring.

The best growing medium as with all blueberries is ericaceous potting compost in a 50:50 ratio by volume with grit and fine chipped bark.

Pests

Birds love them !

Varieties

cv. Aurora – A very late fruiting variety and one of the newest cultivars to be launched. It produces fruit from late August through to very early October. The berries are large and darkly coloured. Best picked when fully ripe to get the greatest results. Has a rich, all-round tart flavour which jazzes up the breakfast cereal and granola ! Strong growing and highly productive.

cv. Bluecrop – the most widely grown blueberry throughout the world. Introduced in 1941 so one of the oldest varieties. It is not only reliable but high yielding – it may be one of the heaviest cropping varieties known. The fruit has an excellent flavour but not quite as sweet as some cultivars. It has a nice ‘bite’ which is achieved by leaving the berries until they have turned completely dark blue for the best flavour. A mid-season variety where the fruits are a delightful powder-blue colour and large. The bush is incredibly vigorous and establishes quickly and strongly. Withstands really wet conditions like cv. Patriot. The autumn colour is tremendous with beautiful deep red leaves. Available from Ken Muir.

cv. Brigitta Blue – one of the latest fruiting seasons. Highly productive, with sweet berries that have an acidic tang. The fruit stores extremely well, lasting up to six weeks if kept in the fridge. Available from Pomona Fruits.

cv. Coville – a late season variety which is ideal for extending the season. The delicious fruit hangs on the plant without dropping. Available from Chris Bowers.

cv. Draper – This large-berried blueberry is an early to mid-season favourite, fruiting from late July until mid-August. The bushes are highly productive. The large, firm berries have a crisp and sweet flavour which sets the mouth tingling. Extremely resistant to many common diseases.

cv. Duke – An excellent early season variety and very productive. Although it ripens early, it flowers quite late so avoids damaging spring frosts. Available from Pomona Fruits.

cv. Patriot – An early variety but not as early as Duke. Will withstand slightly wetter conditions than most. Highly decorative with superb white scented flowers and beautiful autumnal foliage. The fruit is large and has an excellent flavour. Available from Pomona Fruits.