Garden masterclass: how to care for summer fruit

Top tips for fruit

Summer prune trained forms of apples and pears, such as cordons and espaliers, from mid-August. However, in areas where growth is still strong (often the case in wetter parts of the country), hold off until September. Summer pruning encourages flowering and is essential for controlling the growth of trained forms of fruit.

Prune sideshoots over 9in (22cm) long (secateurs length) that are growing directly from the main stem of a cordon or arms of an espalier to three leaves beyond the basal cluster (the clump of leaves at the base of the current season's stem growth).

Prune stems growing from existing sideshoots or spurs to just one leaf beyond the basal cluster.

Delay pruning shoots less than 9in (22cm) long until mid-September. If the trees produce further growth after summer pruning, prune the regrowth in September (or October if pruning later), to one leaf beyond the last cut.

Prune fruited canes of summer raspberries immediately after cropping. Cut off canes flush to ground level; don't leave stubs that could carry disease.

Secure new canes loosely with a string and tie to a support. From September, not earlier, select strongest canes and tie them individually to wires 4in (10cm) apart. Prune out surplus canes. If tied too early, the string cuts into the expanding canes.

Similarly, with blackberries and hybrid berries, tie in the new stems loosely for training later.

Prune back laterals of cordon-trained ("rod and spur") grapevines growing on walls, over arches and pergolas, or under glass, to three leaves past the last bunch of grapes and to five leaves on non-fruiting shoots. Pinch back any subsequent growth to one leaf.

On grapevines in the open, trained using the Guyot system, remove some leaves around grape bunches to allow more light and air movement.

Consider spraying the foliage of raspberries with Epsom salts if the leaves are yellowing between the leaf veins and later developing reddish brown tints (it indicates magnesium deficiency). Other fruit, such as vines, plums and tomatoes, are susceptible – especially on lighter, sandy soils.

Soil-grown fruit does not need additional feeding now, but fruit grown in containers benefits from fortnightly liquid feeding until the end of August.

Soft fruit, in particular, but also stone fruit, appreciates watering during dry periods. And, water apples and pears during hot, dry spells, especially if planted in the past two years and not fully established.

Quick trouble shooter: brown rot

Apples, pears, plums, cherries, nectarines, peaches and apricots can all develop soft brown spots that eventually engulf the fruit.

Brown rot infects through wounds caused by birds, wasps, codling moth and apple scab. At flowering time, this fungi causes blossom wilt, where flowered shoots turn brown and shrivel.

Remove rotting fruit and bury at least 1ft (30cm) deep. Ideally, net trees to reduce bird damage. Prune out and burn branches killed by blossom wilt.

Control of problems such as codling moth and scab (Bayer Garden Systhane Fungus Fighter) will help to prevent brown rot.

^{Brown rot can spoil all kinds of fruit, including plums}

Meet the expert

Jim Arbury, fruit and trials specialist at RHS Garden Wisley, is busy at this time of year: "At the end of August we are busy with summer pruning restricted forms of apples and pears," he says. "This encourages flower bud formation for next year on the stubs that are left."

Jim grows espaliers, vertical and oblique cordons, but summer pruning is the same for all. "At this time of year, growth has slowed. After a terminal bud forms, growth stops, indicating the ideal pruning time," he says. "Don't do it earlier. You get regrowth and the bud formation is often poor. Bush apples and pears are seldom summer pruned, but you could prune laterals longer than 30cm down to 15cm on too-vigorous trees.

"Summer pruning of fan-trained stone fruit is mostly finished," he adds. "But if you haven't done it yet, prune laterals that are not needed to three leaves. Peaches, nectarines and acid cherries that fruit on the previous year's wood are pruned after fruiting."

Harvesting also starts this month: "We are starting to pick early apples, beginning with 'George Cave', 'Discovery', 'Laxton's Epicure' and early cooker 'Grenadier'," says Jim. " 'James Grieve' and 'Delbard Estivale' ripen at the end of August."

Early pears include 'Jargonelle' and, towards the end of August, 'Beth'. "The trick with pears is to bite into them when they start turning paler green and come easily off the tree. If hard but sweet, they are ready to pick. If hard and starchy, they need to be left a bit longer. But if left on the tree until fully ripe, you find that they go mealy in the centre."

RHS news and events for August 2014

Normal garden admission applies unless otherwise stated.

The Great Garden Quest continues through August at all four RHS gardens, with family activities, including crafting classes and building mythical creatures (www.rhs.org.uk/gardens).

Come to the Hyde Hall Flower Show (July 31-August 3) and be inspired by the nursery displays, and pick up some tips and plants. On August 8, Hyde Hall hosts a one-hour guided tour of the Hilltop Garden to look at ways to encourage bats into your garden. This is followed by a trip to Essex Wildlife Trust visitor centre to watch bats emerging from their roosts. Tickets £6 per person, including refreshments (www.rhs.org.uk/hydehall).

Wisley holds Flavoursome Fridays through August with tastings and tips on growing your own from the Wisley fruit team. Also at Wisley, more than 60 sculptures by artists from across the South East will be on display until September 28
(www.rhs.org.uk/wisley).

This month's RHS Secret Garden Sunday on August 3 is in the RHS Lindley Hall, London SW1, with an indoor coastal garden and ice creams served from a beach hut. Talks on garden design and foraging (www.rhs.org.uk/shows).

Visit Harlow Carr on August 3, 10, 17 or 24, and enjoy live music. Learn how to grow edible flowers on August 20 (10am-4pm). Members £40, non-members £48 (www.rhs.org.uk/harlowcarr).

Enter home-grown produce in the local show at Rosemoor on August 16. Plant Heritage holds its autumn plant fair at Rosemoor on August 31, 10am-3pm (01805 626800; www.rhs.org.uk/rosemoor).