Val Bourne offers her top tips for growing blueberries

I am a restless gardener for every time I leave home the sun shines and the temperature soars above 10C. Cheered by the spring-like warmth I promise myself a full day in the garden tomorrow. However when the next day dawns it’s cool, wet and windy once again, so I’m thwarted even in my greenhouse. Frustratingly when I venture from home to visit yet another garden, as I often do in snowdrop time, the sun breaks out with conviction once again. Ugh!

I may be frustrated, but my plants seem to be enjoying the stop-start weather. The blueberries have budded up and begun to flower far earlier than usual. They are grown in wooden tubs full of ericaceous compost because these members of the heather family will only thrive in acid conditions. They are related to cranberries, bilberries and huckleberries and these also need acid soil. Therefore in most areas of England blueberries have to be planted in containers and ericaceous compost must be used. Add 50 per cent grit to the compost to aid drainage because, although blueberries enjoy water in the growing season. They hate winter wet. Ours are moved for this very reason every November, to the lee of the house to keep them on the dryish side. In summer they’re manhandled into the fruit cage, by the Rufty Rufty one, and then watered regularly with water drawn from a butt. Tap water is too alkaline for them. The fruit is irresistible to blackbirds and thrushes and they would devour every nutritious berry before we had a chance to pick any of them if they had the chance.

We have four varieties and they provide modest pickings of fruit that conveniently fill the gap between strawberries and autumn-fruiting raspberries. They crop for five or six weeks, ripening in dribs and drabs, in late summer. Bluecrop, the most widely planted blueberry in the world, is productive, easy and disease-resistant. The firm berries, which are resistant to cracking, can be kept in the fridge for up to two weeks.

The larger-berried varieties, such as ‘Chandler’, have enormous berries but in fewer numbers. We also grow ‘Pioneer’ and ‘Polaris’ and they all make large shoulder-high bushes.One mature bush should yield about five pounds of fruit, although you must feed them ericaceous plant food. Although blueberries are partly self-fertile you get a much better crop if two or three varieties are grown together so that out pollination takes place. You can extend the season by planting early, mid and late varieties and the fact that you can grow them in containers makes them suitable for smaller gardens. If you only have two varieties go for overlapping groups, either and an early and a mid, or a mid and a late so that the bees can transfer the pollen.

Blueberries are very recent: they were sent as a gift from Lulu Island in Canada to aid economic recovery in Britain following the Second World War. Eighty plants of Vaccinium corymbosum (the High bush blueberry) were planted at Trehane Nursery in Dorset in 1951 and they thrived on the acid Dorset soil. In consequence, David Trehane planted up an acre to accompany his equally acid-loving camellias, and the first commercial British blueberry nursery got off the ground in 1957. Some of the original plants still bear fruit, so they are obviously long-lived. Trehane’s nursery sells several varieties. The flavour of home-grown is better, because blueberries are often chilled and stored for supermarket use. Picking and eating them straight from the bush also tops up the vitamin count, for these berries are full of antioxidants.