In the garden: currant affairs

I recently spent a sunny afternoon picking blackcurrants, gently pulling the dangling strigs of fragrant, inky berries off branches so heavily laden that they’d been bent low to the ground by the weight of the fruit.

Within an hour I had picked close to 30lbs/13kg of currants, and been inescapably reminded of the fact that the only downside to growing this pleasingly tart fruit is the backbreaking tedium of harvesting it. But when you consider not only how easy they are to grow, but also the variety of ways in which those tangy, juicy berries can be put to tasty use, it’s a small flaw easily forgiven.

Just one blackcurrant bush will give a yield of about 10-11lbs (4.5kg-5kg) of fruit. That’s enough to make a dozen jars of blackcurrant jam, a couple of large bottles of cassis (the delicious ingredient that transforms a glass of champagne into a Kir Royale), a large Kilner jar’s worth of blackcurrant coulis, several trays of blackcurrant cup cakes, some mouth-wateringly tasty blackcurrant ice-lollies . . . and still have enough left over for some homemade blackcurrant ice-cream, cordial, fool, or even wine. Not only that, but the plant’s tangy, flavoursome leaves can also be used to make a delicately-flavoured sorbet, a lemonade, or a herbal tea.

It’s tastiness and versatility aside, the blackcurrant’s health-enhancing qualities are well known.

During the second World War, for example, blackcurrant cordial was used in hospitals, schools and nursing homes in the UK to treat vitamin C deficiency. The cordial was made by the same company that manufactured Ribena, the fruit drink that, interestingly, gets its name from the Latin term for the blackcurrant, Ribes nigrum.

Scientific studies have since found that both the fruit and the leaves are also rich in many other health-boosting phytochemicals. The colour of those inky berries, for example, is an indication of high levels of anthocyanins, a powerful type of antioxidant that helps our immune system to fight infections and can help reduce the risk of cardiovascular disease, lower levels of bad cholesterol, fight obesity and reduce high blood pressure.

Other studies suggest that eating blackcurrants can help with brain function, eyesight function and urinary tract health, while herbalists use both the leaves and the fruit for their anti-inflammatory properties, as a hormone regulator and to improve circulation. It is, in short, a wondrous plant.

How best to grow it? Blackcurrant bushes can be planted as bare-root specimens anytime between October and March. Container-grown specimens can be planted at any time of the year, but need to be kept well watered if planted in active growth. You can also easily grow the plant from 8-inch/20cm hardwood cuttings taken in late autumn.

Although blackcurrant bushes tolerate light shade, they do best in full sun and in a rich, well-drained, weed-free soil enriched with plenty of organic matter. Avoid planting in a frost pocket or in a windy site.

If you want to grow the plant in a container, make sure it’s a large one, at least 18-inches/45cm in diameter and 12-inches /30cm deep, and use a good-quality John Innes compost. Give container-grown plants a balanced fertiliser in March and aim to re-pot them, using fresh compost, roughly every three years.

A host of different varieties are available. Among the best are the “Bens”, bred by the Scottish Crop Research Institute. In particular look out for the heavy-yielding, flavoursome “Ben Hope”, which has exceptionally good disease- and pest-resistance. Where space is tight, choose “Ben Sarek” or “Ben Gairn”, both compact, high-yielding varieties that produce lots of large, tasty, juicy berries. If your garden or allotment is prone to waterlogging, try “Ben Connan”; if it’s vulnerable to late frosts, choose one of the later-cropping varieties such as “Ben Alder” or “Ben Tirran”, while if you like sweet berries, choose “Ebony”.

Careful pruning is essential to productivity, as the majority of the berries are produced on new growth. Without it, the bushes form a thicket of straggly woody branches, but far fewer, smaller berries.

With young plants (up to and including their fourth year in the ground), remove any weak shoots once a year during the dormant season to leave a framework of six to 10 strong shoots.

After that, continue to prune annually, removing any weak, spindly growth along with roughly a third of the plant’s shoots, choosing those that are the oldest. An autumn mulch of well-rotted manure will help to suppress weed growth around the base of the plant, while a shovelful of ash from a wood fire will add potash and help with fruiting.

Net the ripening fruit from birds, and always harvest the berries on a dry, warm day to prevent them going mouldy.

Some gardeners like to double-up on the tasks of pruning and harvesting by cutting out the oldest third of the plant’s berry-laden branches and then bringing them indoors, where the fruit can be comfortably handpicked while sitting at the kitchen table. Any not-quite ripe blackcurrants can be left to ripen by placing the bottom of the branches in a bucket of water.

As harvesting methods go, it’s certainly a lot easier on the back. Just beware the inevitable escapees, those berries that slip through the fingers like marbles before skittering off in a dozen different directions, and inevitably getting stood on. Which brings us to another important use of blackcurrants, which is as the source of an extremely persistent, violet-coloured dye.