Getting to grips with pruning My family used to join in a community gardening session around the meeting hall. We all chose a job. My dad’s enthusiasm for pruning was in complete contrast to his knowhow. He chose a very twiggy shrub about meter high which had spread widely and when he had finished there were about 5 stems left. He assured my horrified mother ‘It’ll grow’ and though we all doubted him, it did. Plants are pretty resilient. There are a few specific do’s and don’ts but if you follow some general principles you probably won’t kill the plant. The likely worst-case scenarios are that you ruin the shape for some time to come or stop it producing flowers and fruit for a year. Pruning stimulates growth in woody plants, and you need to do it when there is enough time (some months) for the plant to respond and the new growth to harden before winter. Alternatively prune in the dormant period. It’s useful if you can work out what the plant is, though it isn’t essential. This helps you to decide your purpose. Please remember, that in many cases pruning is not needed. Many plants don’t insist that you prune them. Reasons for pruning include such things as encouraging more flower and fruit; containing the size of the plant; and getting bigger leaves or more brightly coloured stems. Perhaps the plant needs rejuvenating? Have you just had a row? All good reasons! Pruning is cathartic.Choose a frost-free day. Also avoid pruning when the ground is soggy, walking on wet soil will compact it. And perhaps take a deep breath if you have just had a row. Make sure all your tools—secateurs, loppers, shears, saws—are sharp and clean. The cuts should be clean so they heal more quickly. If spines or prickles are involved, wear eye protection. Firstly, remove any dead, diseased or damaged wood. Cut back to a point where the remaining wood looks healthy and no longer has a dark centre or unhealthy bark. There is no need to remove lichen (pictured), it is harmless and quite pretty. If any branches are rubbing each other, remove at least one. Remove any weak growths, which are thin compared to the main shoots and create a cluttered effect. The prevent a good flow of air within the branch framework. Feeling better? Excellent! You can stop there. But by now you will sense how absorbing pruning can be. So, if you still wish to move forward whilst creating the least damage to your plants, you now have to have both a clear purpose in mind and know one basic principle of how a woody plant grows. It is called ‘apical dominance’, or put another way, the growing tip is the boss. The bad news is that plants are more hormonal than teenagers. The good news is that they react fairly predictably to pruning which alters a key balance of hormones. Apical dominance is the result of hormones interacting. Auxin is the hormone produced at the top bud and it encourages forward/upward growth. As it travels down the stem, this hormone suppresses growth in the side shoots. That is why trees have single stems for their first years. If that top bud is damaged (eaten or pruned away) the flow of auxin dries up and the side shoots take over and grow away from the trunk creating a shrubby shape. The end bud of each side shoot starts to produce auxin to encourage it to grow.Cutting hedges results in removal of all the end buds, both on the top and on the sides. The lower buds and shoots on each stem sprout and that creates a thicker hedge. If you want a shrubby plant from rooted cuttings that have been growing for a year, remove the top bud (apical bud). In both instances, you are removing the apical dominance. If you want a tree then keep that top bud; or if it gets destroyed, encourage another shoot that has a good bud to take its place. You are encouraging the apical dominance to get the young tree to grow tall. A young tree will have side shoots after a while. To encourage the main stem to be the only trunk, remove a few of these side shoots each year in early spring from the base upwards. Don’t take off too many. The plant stores nutrients in all its parts, and in the early years strong growth results from good stores. A popular form of pruning involves shaping woody plants into formal geometric shapes such as lollipop trees, box balls, or domes. ‘Topiary’ is the word for individualistic shapes like birds or other animals. With practice you get good at this type of pruning. A hand-held topiary saw is a great tool. Another popular and practical purpose of pruning is to shape and prune plants against walls. As walls radiate some heat, they are often used not only for less hardy plants but also for hardy ones such as fruit trees. Climbers such as clematis and roses are often trained against walls. To train them, you aim to form a framework out of the plant. The basic idea is to train the appropriate stems into the right place, fixing their growth to the wall to as near to horizontal as the shoots permit. Doing this breaks the apical dominance of each of these shoots. This works for plants such as apples and pears and some roses. Once that apical dominance is broken, the side shoots of the fixed-in horizontal stem will break and grow. These side shoots develop flower and fruit buds, so your wall will look lovely when the plant is covered with flowers and later fruit. Cutting off too much in one go results in lots of new twiggy sprouts (because of -- you guessed it —hormones), which generally need to be thinned. If the pruning is proportionate it can result in more colour and larger leaves in the new growth. The nutrient stores that have remained on the plant are divided amongst fewer shoots and leaves. Don’t remove too much if the plant hasn’t been pruned each year. Hard pruning can shock or even kill a plant. My dad’s effort recovered, but it took a few years, so if you need to prune a neglected plant do it over several years. A good mulch after you finish will help replenish some nutrients.