Blueberries/ Bilberries are healthy fruits which will grow extremely well in containers. Of course, these plants can cope perfectly well outside but placing them in containers in your polytunnel will save the crop in the event of bad summer weather and can also make it easier to protect your fruits from being eaten by birds before you get a look in. Blueberries are native to North America and other locations, while bilberries (also called blaeberries in Scotland) are found in the wild in the UK.
One of the reasons why it is a good idea to grow Blueberries/ Bilberries in containers is that they require an ericaceous (acid pH) growing medium – a medium not ideal for growing many other fruits and vegetables. Water with rainwater rather than tap water whenever possible as tap water can raise the pH. Blueberries/ Bilberries can be very fussy about the pH, so keep that to a constant of pH 5.5 for best results.
Young blueberry plants can be obtained throughout the year, though usually it is best (and cheapest) to choose dormant plants and plant them in the late autumn or winter.
While some Blueberries/Bilberries will do fine planted individually, some will produce a better crop if planted near another cultivar. They will also do better if the containers they are in are free draining yet moist. Pine needles make a good mulch for acid-loving plants and crocks in the bottom of your containers will help retain moisture.
Containers should be at least 30cm wide for young blueberry plants. When the plants grow, you should graduate them to 45-50cm containers. Replace the ericaceous compost every few years or you are likely to see a drop in productivity.
For the first couple of years a blueberry plant will not need to be pruned. After that, however, it is best to prune your plant in the dormant period each year to maintain its vigour and berry production. Aim to remove a portion of old, less productive wood each year to leave space for new growth.
Blueberries/ Bilberries will, of course, be ready to harvest when they are a deep blue, in the mid to late summer. Not all the fruits on your blueberry bushes will mature at once so you will have to harvest over a period of time. Fruits not harvested in time will drop off the bushes. When harvested, Blueberries/Bilberries can be eaten right away, or cooked into pies, puddings or preserves. These are very versatile fruits with many uses in the kitchen.