Some advantages come with age, though I can’t think of many as I sit here wearing glasses watching my wrinkly hands. But when it comes to plants, there are some good points. Although some plants have especially distinct juvenile and adult phases of growth, in most others there are subtle changes. When these familiar garden plants are juvenile they are excitable and intent on growing and don’t think about the tricky business of reproduction, which to us means flowers and fruits. What is more, if given encouragement, a plant in a mature phase can regress to a juvenile phase again which can puzzle gardeners.
Think of that camellia you bought. It was in a mature phase because it had filled its pot and ‘thought’ it could not grow any more. So it produced flower buds. When you got it it was covered in buds and it flowered that spring, much to your delight. Provided you watered it and it survived, it then discovered there was lots of soil to explore and it put on lots of growth. The result was no flowers the following year. And maybe not the year after. What on earth went wrong? Nothing. This is just what plants do. The same happens to wisteria, which may have been in bloom when you bought it but then romps up the wall and you get no flowers for years. It has a one-track mind with no distractions.
Without the drain on resources that flowering causes, the plants grow like mad. And if you prune them, wrongly, to discourage flowering, the plant just keeps on growing. When plants start to boom or fruit, they make less vigorous growth and that stabilises the plant and brings on more flowering or fruiting. We need to encourage plants to get to this mature state and discourage the juvenile state, in plants that we want to flower and fruit.
That is what summer pruning does. We summer prune in August, when it is too late for dormant buds that are left, to sprout. In the case of most plants, including apples, pears and wisteria, we cut back to four leaves. If we prune in spring, it encourages rampant, juvenile growth – useful in some cases – see below.
But looking at these two apples trees, above and below. Above is a mature apple tree – well actually very mature. It is in a stable cropping cycle. It carries a good crop and that regulates new growth. You can see that there are no huge shoots, just spurs that will crop next year.
Compare that with the young tree below. This is five years old and is carrying a crop but it is still keen on growing. This is good but to keep it compact those long shoots will be pruned back to four leaves this month. I do it every year. It will create a well branched tree that is compact and with fruit low down where it can easily be picked.
My apple trees at the new house had a tough year last season. They made very little growth because of the drought. I wanted them to make good growth in the first few years and fruiting is not important. It is better to get them to grow well. So this spring I hard pruned them specifically to push them back into the juvenile phase. I will not summer prune them because I don’t want fruit yet. Instead I will prune them again in spring, reducing their growth by half or two thirds. This will make them better branched and balanced. With luck I will then summer prune next August. Watch this space for pics of the apples.