An espalier is one way to train apple trees.
Despite being cold and wet, July is a month with quite a few gardening tasks to be completed.
This is the time to do winter pruning. Trees are pruned for many reasons.
Often they are practical reasons of how they impact on our lives, such as to ensure a tree is not blocking light into a home, or a branch may be protruding over a driveway or constantly dropping leaves into the spouting that someone decides they no longer want to clean out.
For fruit trees, pruning is important to maximise fruit production and ease of harvest.
For plants like roses, pruning is to maintain a compact bushy plant with a strong flowering display.
If left unpruned they tend to quickly become scraggly in growth and sparse in their floral display.
The pruning of roses and many deciduous trees and fruits is best completed during the winter months when these plants are dormant and deciduous have lost their leaves.
The timing of pruning is one of the keys to success, as well as making the right cuts.
Roses and deciduous fruit trees such as apples and pears are best pruned during the month of July.
If it’s done any earlier – particularly in areas with a temperate climate – there is the risk of getting a warm snap that makes the plant think it’s spring.
The plant might then produce new growth that risks getting walloped by a July frost.
Pruning is best done on the kind of day when you would hang your washing outside.
Pruning on a warm day is not only more pleasant, but significantly decreases the risk and spread of bacterial and fungal disease.
It is important to ensure that cuts that are made are “cleanly” angled to prevent water pooling on the cut.
I highly recommend the use of a pruning paste such as Grosafe Organic Prune ‘n’ Paste or Yates Prune Tec to seal the cut ends of branches, as this will minimise the risk of disease and insect invasions, which shorten the life of a tree.
Rose pruning is essential to reinvigorate the plant, promoting new growth and subsequent flower development.
Many people aren’t sure where to start when pruning.
It is important to use the correct tools, as too small a tool will make any job difficult.
Use secateurs for small, twiggy growth, loppers for small branches and a pruning saw for larger branches.
The first step is to simply remove any dead, diseased and badly insect-infested branches and carry on from there.
Where prunings are diseased, it is important to burn them or send them out with the rubbish rather than composting.
Thin, weak stems should be removed, with stronger ones retained. Inward-facing and crossed branches should also be removed.
The aim is to open the centre of the plant up to allow increased airflow, which reduces insect and disease infestation in the coming season.
The remaining branches should be reduced by up to three-quarters in the case of a bush or standard rose. Climbing roses should be pruned by approximately half.
Laterals should also be shortened by two-thirds, back towards a main leader.
Fruit tree pruning is primarily undertaken to allow sufficient light to penetrate into the canopy area to maximise fruit set, yield and quality. Here are some pointers on pruning and training some fruits.
Almonds are usually pruned and shaped as vase-shaped trees. Train the tree to three or four main limbs.
Almonds fruit mainly on short spurs that bear for up to five years. Prune out about one-fifth of this wood each year.
If numerous suckers arise in the centre of the tree, they can be removed in summer.
Keep a strong sucker and allow it to grow if a replacement limb is required.
Old but still healthy trees can be stimulated into good growth by heavy pruning.
Apples, pears and other pipfruit trees have been trained and pruned to various traditional systems for many years, including open centre/vase shape, central leader and espalier. The central leader system is predominantly used.
In this, a single central vertical trunk is selected to support the fruiting branches.
The branches radiate from the main trunk and form a Christmas tree-type shape.
This allows maximum sun exposure for branches, with the lowest branches being longest and the branches getting progressively shorter up the trunk.
Apples and pears produce flowers and fruit mainly on the two-year-old and older shoots, and on short spurs produced on the older wood.
These trees need a moderate prune during the winter to stimulate growth for the next season’s fruit and to maintain an open, well-balanced tree structure so the tree crops well, the fruit is of good quality and the branches are strong enough to carry the weight of a heavy crop.
Open centre / vase form means the centre leader must be removed and 3-5 major limbs are encouraged to develop.
This vase shape allows good air movement through the tree as well as good light on to the branches.
This method of training is highly recommended for peach, apricot and nectarine trees.
Espalier is best when the wall or fence that is chosen faces north and receives at least six hours of sunshine each day.
The tree needs to be trained from planting, with unwanted branches removed depending on the shape you want to train your espalier to.
Research by experts has identified that the best-flavoured and biggest fruit are produced in the largest quantities on branches that grow 30-120 degrees from the vertical, with the best branch angle being 30 degrees above the horizontal.
Apricots bear fruit on short spurs that form on the previous year’s growth and on older spurs that can remain fruitful for up to 3-4 years.
Pruning is aimed at maintaining the shape of the tree and removing any old, unproductive wood.
Prune and train an apricot tree to a vase shape.
Protection of pruning cuts is necessary in apricots to prevent the entry of silver leaf and bacterial blast infections, which can also attack plums and cherries.
Use a pruning paste over all cuts to assist healing and help prevent infection.
Apricots and other stonefruit are best not pruned now but left until the summer. This will lessen the risk of silver leaf infection.
Cherries fruit on spurs on 2-year-old and older wood.
Older trees should be pruned in summer to restrict vegetative growth and induce the formation of fruit buds.
As a winter prune, spurs may be thinned or shortened and the branch leaders pruned to shorten replacement laterals to reduce the tree height.
Upright or over-vigorous growth should be removed or tied horizontally to balance tree growth as required.
Note that the vigorous growth of cherries may be inhibited by growing them as a fan espalier.
As for apricots, some summer pruning is recommended to lessen the risk of silver leaf and stonefruit blast infections.
It is also advisable to construct a frame and cover it with bird netting to protect the fruit, for your own benefit.
Peaches and nectarines bear fruit only on the shoots produced the previous year.
Pruning is carried out to encourage new growth and replacement shoots to maintain a balanced and open branch framework in the tree.
There are three different kinds of bud: plump fruit buds; small, pointed-growth buds; and triple buds that have a plump central fruit bud with growth buds on either side.
On branches where extension growth is required, prune back to a growth bud or lacking this, to a triple bud.
Summer pruning is recommended to lessen the risk of silver leaf infection.
The objectives of good pruning are to maintain the size and quantity of the fruit, remove dead and diseased wood, train the young tree so it will develop a vigorous strong framework, train the tree to a form (vase shape, central leader shape etc) and provide healthy, good-quality, evenly distributed fruiting wood throughout the tree.
Note that every time a pruning cut is made, plant growth is stopped in one direction and encouraged in another. Always make cuts back to or just above some growing point.
There are also live pruning demonstrations and useful gardening talks that can be attended during July at Springvale Garden Centre at 2pm on Sundays. July 6: Pipfruit tree pruning; July 13: Orchid growing advice; July 19: No fuss, no-fail vege garden; July 27: Gardening in small spaces; August 2: Introduction to bonsai; August 9: Landscape design principles.
Gareth Carter is the general manager of Springvale Garden Centre in Whanganui.