Garden Guru: Branching out

Espaliers are best tackled in summer months. Photo / Supplied

One of the great pleasures of visiting long-established vegetable gardens is to see fruit trees trained and tortured into all sorts of fantastic shapes.

It may be stonefruit such as cherry, peach or apricot fanned flat against a sunny wall, or pipfruit like apples and pears, which are traditionally espaliered or trained into cordons.

The shape isn't crucial, it's more a matter of regular trimming to make fruiting spurs and bending the branches towards the horizontal that ensures a high yield on a tight space while decorating the garden at the same time.

An espalier involves training pipfruit into a series of horizontally branched tiers about 60cm apart, arranged flat on a wall or on posts and wire along a pathway.

It looks difficult to achieve, but as there is still time to be planting fruit, I asked Waimea Nurseries in Nelson - one of our main wholesale fruit producers for garden centres - how best to do it.

Marketing manager Kate Marshall says it is easy to be creative once you have your fruit trees in the ground.

The big challenge is being brave enough to cut your newly planted tree in half straight away. Ideally, your single trunk should be cut just above a bud at the point where you want to create the first arms, which you will train sideways - usually about 1m from the ground. With its leader missing, as the plant begins to grow it will naturally produce several new shoots, two of which you can gently tie down along horizontal wires or canes.

Kate cautions against being too enthusiastic at this stage - always leave the last third of the branch loose so it can carry on extending.

Having begun to create your first two arms, tie the strongest remaining shoot vertically upward ready to form the second-storey and remove the rest.

When this shoot reaches your next wire in early summer, again behead it so it produces several branches and repeat the same process as you did below.

If your soil is freely drained and fertile and there is water about, a new tree may produce its first tier and the beginnings of the second in the first year. Cordons are simply unbranched leader shoots either planted at a slant or trained near the ground horizontally. Several of these together can make an attractive low single strand or step-over cordon which you can wrap around your potager as a functional and pretty edging.

Kate says most apple and pear varieties adapt well to this severe treatment. Summer and not winter is apparently the best time to maintain your established framework as cutting back all the leafy side-shoots then will curb a tree's vigour and initiate more fruiting spurs. "At Waimea, the side-shoots of all our espalier are cut back by half in early- to mid-summer," says Kate, "and then by half again in late summer."

In choosing apples or pears, you should be aware that pipfruit is usually grafted on to either a dwarfing rootstock variety (getting about 2.5m high) or a semi-dwarfing stock on which an unpruned tree would reach about 4.5m.

Most pipfruit need to be planted in pairs so one variety can pollinate the other. Choose varieties that flower at the same time or try one of the double-grafted trees, which have two or three compatible varieties on a single trunk.

Many commercial apple varieties, including Braeburn and Royal Gala, are not well suited to home gardens because they rely on pesticides to provide a good yield. Granny Smith is an exception and a great pollinator for many other varieties. Most heritage varieties have proved themselves over a long time in our climate, such as the cooking apples Belle de Boskoop and Bramley, and pears Beurre Bosc and Williams' Bon Chretien.

But don't be afraid or trying something new. There are plenty of modern varieties coming through - aimed at today's organically minded shoppers - which have been specially bred for disease resistance.

Warmer climates are not so favourable for growing many varieties because of disease problems such as brown rot, bacterial blast and blackspot, so it's always best to get advice from knowledgeable staff at garden centres.

Most winter fruit is field-grown and lifted a few weeks before sale and sold either bare-rooted or balled up in compost.

Bare-root stock may be found in bins of sawdust at the garden centre and is a more economical choice but only buy if you can see that the roots have been kept damp.

Bare-root trees will often grow just as easily and quickly as potted specimens.

Some promising recent arrivals Kate recommends are Initial, a rosy red dessert apple bred in France with high resistance to blackspot; Baujade, a Granny Smith lookalike that grows well in warm areas and is very disease-resistant; and Blush Babe, a dwarf variety which creates a neat mop-top and is self-fertile, so can be planted alone.

BASIC CARE

* Good hygiene and cultural practices are essential for producing organic fruit.
* Grass can act as a mulch and may harbour beneficial insects and pollinators so don't be afraid to let it grow around the base of your trees.
* A copper fungicide spray once in autumn and twice in early spring before and after blossom is the most important safe spray you can apply.
* Wrap corrugated cardboard around apple and pear trunks to trap overwintering coddling moths. Peel off and destroy in August.
* In winter reduce fungal spores by thoroughly raking leaf litter away from tree bases and cut off any mummified dead fruit hanging on the tree.
* Most winter pruning involves opening out the centre of established trees to let in air and light and removing weak and crossing branches.