Quince trees are still a common sight in the UK, although they have been replaced in some gardens by their more attractive shrub cousins as the household skills of jam-making and preserving have fallen out of favour. The tree has become more popular thanks to its tasty pear or apple-shaped fruit, but its ungainly shape make it a bit puzzling when it comes to pruning.
Plant your tree in a sheltered place in soil that will hold moisture and let it grow for several years. Yes, it is ungainly and a bit ugly. It will grow to about 3 metres (10 feet) high before it needs pruning and will have a few good crops of quinces in the interim. Notice how the tree blooms on the ends of the branches each spring. This habit of bearing fruit on current growth is called "co-terminal." By the third year or at about five years of age, it will need a bit of a trim to look respectable.
Prune your tree during the early winter just before it goes dormant. The first time the tree is pruned, inside branches should be pruned down to an outward-facing bud, no more than a third of the length of the branch. The goal is to open up the centre of the tree into a "vase" shape so that leaves and fruit get sun. Quince trees do not rely on regular pruning to remain vital, but fruit-laden branches will split or break in high winds.
Keep track of when you prune your quince to identify the best time to prune without cutting down the next year's production too drastically. To maximise fruit yield, prune the tree before it goes dormant so it can start nodes from which to grow branches under the cut to fruit next summer. Try not to prune too many branches in a year. In any event, cut a minimum of branches to keep the quince producing. If "hard" pruning -- removing whole branches or taking more than a third off a branch -- is needed to revitalise an old tree, do it after the tree has gone dormant in the winter.
Choose a branch or two each year that has grown long and needs support when it is full of fruit. Prune it back no farther than a third of its length to encourage it to branch and grow stout. Prune shoots that grow inside the tree all the way back to the branch. Because quince leaves are so large, the centre of the tree must be kept open to minimise the chance of leaf infections or pests that also affect apples and pears. Always seal branches after pruning.
In succeeding years, prune sparingly to maintain the "vase" shape or shorten branches that have grown too long to hold fruit. Quince can also be pruned in a flat shape against a wall -- providing it is not exposed to drying winter winds -- or trained like an apple tree.
Always cut branches at a slight angle away from the centre of the tree so that rainwater will run off the end of the branch and not pool on it.
Remember that pruned branches may not produce fruit next year.
Don't take more than a third off the length of a branch at a time.