Once soft fruit has been harvested, many plants can be pruned. There are several important reasons for pruning fruit bushes. Plants produce much more fruit on new, vigorous growth. But, as stems become old and woody, harvests decline and the fruit gets smaller and sparser.

The old branches crowd out and smother new shoots. Before long, the bush becomes a dense, impenetrable jungle and harvesting becomes a nightmare. Although we often want red berries, we don’t want to get this by splattering them with blood from our thorn-ripped flesh.

To ripen well, berries need the light and the sun that’s been sadly absent this year. Like me, you’ve probably noticed that fruit has been pretty tasteless through lack of sun. But we have to give our poor wee berries the best possible chance by pruning away congested growth. And, as I’ve often said, good air circulation keeps plants healthy and prevents fungal rot.

There are different ideas as to when to start pruning: either shortly after fruiting, or during the dormant season. Inevitably either course of action has its pluses and minuses. An early prune cleans up a plant by removing damaged or diseased growth, thereby preventing any build up of disease. The new growth is kept healthy and wounds from pruning are healed without the possibility of die-back which can result from a winter prune. And though the plant continues to put on more growth than you’d ideally want, it’s easily snipped off in the spring.

On the other hand, a mid or late winter prune removes all unwanted growth in one fell swoop, is less disturbing for the plant and encourages it put all its energies into the remaining branches and stems. As you’ll have gathered, I prefer an early prune.

I’ll be concentrating here on currants and species that throw up replacement branches every year - brambles, loganberries and Tayberries.

Currants, black, red and white, produce strong new branches every year, but continue to bear fruit on older, woodier stems with short, new side-shoots along the old branches.

Many gardeners have traditionally removed all the old blackcurrant branches and relied solely on new growth. In Scotland, with a short growing season, we need to keep some old branches for a good crop.

You need to cut out, right to ground level, one third of old blackcurrant branches, especially the gnarly ones. Aim to leave 5 or 6 main branches, preferably 2 old and 4 new stems. Shape like a goblet, round an open centre. Remove all low-lying and crossing stems or side-shoots and any spindly growth in the centre of the bush.

With red and white currants, aim for a similar shape of bush, bearing in mind that 2 year old branches produce heavier crops than new ones. So, you should end up with 4 or 5 older year old branches and one new one. Again remove all low branches.

Even more drastic action is needed with raspberries, loganberries, brambles and their close relatives. This group only fruits on new growth, so this year’s fruiting canes must be completely removed. As with the summer fruiting raspberries I mentioned recently, the long fruiting stems of brambles, loganberries, and Tayberries must be cut right back to the ground, leaving room for the fresh stems.

Apart from a few new bush varieties, like ‘Navaho Big and Early’ bramble, most of these plants produce several very long stems every year and you should only leave 3 or 4 strong new stems to fruit next year.

Because the stems may be 5 or 6 metres long, they’re best trained along wires on a wall or fence. You can reduce the space needed by hooping stems between horizontal wires that are 60cm apart. Roughly bundle the new growth on the ground till you’ve cut out the old stems.

Growing pains

This year I bought ten new summer fruiting raspberry plants. Three just died: two produced canes from the newly planted stump with a couple of fruits, but no new canes for next year. Of the remainder, only one has a couple of new canes over two feet high, and the others have produced mainly poor-looking canes no more than a foot high. I know this has been a particularly chilly summer, but I expected better performance. Should I persist with these plants, or cut my losses and replace all or most of them? Ron Flett, Glasgow

I assume you planted in fresh ground, not where you had previously grown raspberries [or even strawberries]. If you had, replant sickness would have explained your problem. I'm also assuming the canes were healthy and moist when you got and planted them. Otherwise they would have been stressed and possibly dead already. Did you cut back the new growth to just above ground level after planting? This lets plants put their energy into producing canes for the following year. You would not expect any harvest this year.

Cut your losses, dig them up and start again - in a different bit of ground.

Plant of the week

Euonymus Europaeus 'Scarlet Wonder' produces some rich scarlet colour for autumn, with arching branches drooping under the weight of rosy, red fruits.