01/08/2019 To pinch or not to pinch (that is the question)
Following on from the interesting August 2019 blog by John Willis about whether we should pinch or prune juniper bonsais I thought I would give my thoughts and reasoning. As John says, historically bonsai books and teachers advocated regular pinching of juniper growing tips to maintain the trees shape and to discourage juvenile growth. However, many modern bonsai artists and teachers say this method weakens junipers over time and advocate allowing the growing tips to extend somewhat and then cutting back the growth to maintain the trees shape. The usual reason given for this approach is that junipers develop strength and vigour more through extension growth of their foliage than through their roots as in most other types of trees.
Over the years I have used both methods of pruning. Initially I used to constantly pinch back the growth (without any apparent adverse effects). However I now allow the tips to extend much longer before cutting back to maintain the shape. I believe that my juniper bonsais, using the cutting back method, grow better and are healthier trees as a result. Any bonsai trees health and vigour (deciduous or evergreen) benefits from being given the opportunity to grow for periods without any pruning back. It is for this reason that I now think it is more beneficial to allow junipers to extend their growing tips before pruning to have sufficient time to build up essential strength and vigour. See the pictures below of growing tips being allowed to extend on an Itoigawa juniper.
On a similar topic there appear to be differences of opinion about whether allowing a bonsai tree to fruit or seed weakens the tree. I have a large larch bonsai that produces a large amount of cones most years (see picture below). Some say it is the trees way of regenerating new offspring in order that it can die. They say I should remove the cones to prevent the tree from dying. For a number of years I have done this. However, I like to see the cones and a well-known bonsai artist recently told me that if the tree looks healthy there is no need to remove the cones. I have left them on this year and I am keeping a keen eye on the trees health. I don’t know if they are correct and I would hate the tree to die but again, who do you believe?