Winter work in the orchard June 19 2015, 0 Comments
Winter is down time for fruit trees, but not for humans if they want a good harvest.
Jill Redwood tells how she keeps her Goongerah, Victoria, orchard thriving.
EARTH GARDEN June – August 2012
The orchard in winter is beckoning to be worked on. On a fine day, grab the pruning gear, buckets and barrow and enjoy the winter sunshine while pruning, cleaning and doing a stock-take in readiness for the coming spring.
Our deciduous fruit species all experience a kind of hiatus through winter. During this lull it might appear as though our trees and orchards are in deep slumber, but there are still many magical things happening.
Fat fruit buds are gathering energy for spring, soil microbes and fungi are busy underground, worms are recycling nutrients, and in the temperate climates, the trees are tallying up the amount of chilling they receive so they can deliver a fantastic bounty of fruit for the coming season.
The more hours of cold winter temperatures less than 10 degrees, the better the fruit production will be. Even an alpine chill of minus 10 and 20 can be withstood for an acclimatised tree. But there are also varieties that have been specifically developed for areas in New South and Queensland where the winters are cool rather than cold.
After the tree has ticked off the needed chill time, it then tallies the right number of warmer hours. It’s a bit like chooks that start to lay when some inner magical apparatus senses the lengthening daylight hours at the end of June. The fruit tree also senses the right amount of chill and warm, then decides to burst its little spring buds. Different fruits have different needs but it’s roughly 800 to 1200 hours of chilling. Good frosts and plenty of cold also help knock out orchard nasties like fruit fly.
Trees that do the dormant pause for winter include apples, pears, apricots, plums, cherries, walnuts, hazel nuts and the bush or cane fruits like currants, gooseberries, raspberries and blueberries. Those that like a milder winter include the citrus, figs, grapes, almonds and, of course, all the tropical fruits. In colder areas you can plant the sensitive trees like citrus on a slope that drains cold air, rather than in a frost pocket that holds it. While they are young, you can also cover their tender foliage with hessian or shade cloth when it looks like a bad frost — or build a permanent frost hat over them until they are bigger and become hardy. They especially dislike having the first rays of the sunrise hit their frozen leaves. They prefer gentle thawing in the shade or with a sprinkle of water.
So what do you do in the winter orchard? It might be rest time for the trees and bushes but not for us! Pruning and checking for health problems is the main game for winter. Without a cloak of leaves the tree’s structure, problems and inner being are revealed. The winter orchard tasks include:
• Pruning out the old canes from berries and current bushes;
• Untangling and thinning out the rampant growth of the fig;
• Pruning back the grapevine to its T-shape structure with spikes;
• Planting and cosily tucking into a prepared hole any new trees you’ve bought, keeping the graft site above soil level;
• Prune apples and pears (this is the time of year I always realise that one apple and one pear tree is plenty!),
• Protecting young citrus from frost;
• Picking off mummified hanging fruit and destroying it;
• Pruning peaches and nectarines now that you can see their form;
• Checking for evidence of pests like wooly aphids (dense warty growth on limbs and branches or white fluff in twigs), borers (holes and sometimes webbed rings around a branch) and bacterial gummosis (weeping gum patches); and
• If the apples had scab or black spot last season, piling raked leaves all the way around and under the tree by the end of winter. I use eucalyptus leaves when doing fire safety clean ups. The leaf cover buries the spores and stops rain splash back onto the tree. A new trick I’ve just learnt, and it works a treat.
Each type of tree has its own special pruning techniques. There’s not room enough to detail them all here, sorry; you’ll have to read a pruning book. It can be complex but so satisfying when you realise how the branches and hormones of a tree can be trained to produce generously. But try to keep the tree a sensible height. You don’t want to be climbing four-metre ladders to pick apples. I’ve been there and believe me, it’s better to train them down to the horizontal rather than let them have their vertical freedom! Skywards-reaching dominant branches are a waste of the tree’s energy and discourages fruiting.
If you want to cage them for summer, keep them low and compact.
Except for citrus, which can be left happily alone, what all fruit trees need is decluttering. This means cutting out dead branches (shrivelled and cracked), tangled or crossed branches, the scrambled thick innards and any diseased limbs and twigs. You can feel them breathe a sign of relief when they’re opened up and it helps stop them getting problems like woolly aphids. A sparse and well-ventilated tree is a healthy tree.
Fruit or branches that hang below knee level are the perfect highway for soil-stored diseases. So while you’re busy with the pruning saw also take out these branches that have stooped down to the ground under their load. These will be replaced slowly by the next branch layer above bowing down in an ongoing cycle over the years.