Updated: Jan 7
Pinching juniper bonsai is often something you will hear about and there is a divide between those who advocate for it and those who don't, I've heard conversations from both sides so lets see if we can sort this out. In the red corner we have pinching and in the blue corner we have no pinching, which juniper will come out on top?
First of all lets talk about pinching in general, this is a misunderstood practise in Bonsai and is one of those things people do because they hear professionals talk about pinching, so more often then not they venture out into their garden and start pinching all their trees like an overly affectionate grandma with her grandchildren. Often times the trees feel like the kid, they see grandmas nippers coming and prepare for sore cheeks. The keen bonsai hobbyist walks away feeling a lot more like a professional because they have successfully pinched their trees. but why? Well that their not sure of.
Pinching is reserved for more refined trees and done at a particular time, We wont go right into pinching now but basically it is largely practised on deciduous trees to control internode length and prevent a branch from getting overly vigorous preventing the branch taper from running out of control. so after the first flush on a maple for example as the first 2 leaves open up and take shape you will notice that in the centre of the 2 leaves there will be another node beginning to push with another 2 leaves. You would pinch this new growth out as it begins to open to prevent the branch from getting too strong. This will result in your internodes being closer and your branches will get thinner and thinner as they build out. But you don't want to do this year after year after year because you are essentially preventing the tree from creating a decent amount of energy for itself while it is spending more then its making. If your maple had an energy accountant they would be mortified by the numbers and would soon be begging you to put some energy in the bank as a saving account so you don't go bankrupt.
So how does this conversation get moved over to Junipers? The thought process was much the same, pinch the newly grown growing tips off which will supress the growth and result in finer branch ramification. There are lots of old books that teach this method, there are also some of the older generation who still teach this method and i have even spoken to an apprentice in japan who is studying right now who says his oyakata promotes pinching junipers. Now, im going to say the books and the older generation teaching this are stuck in old methods, Obviously the book cant change and those who came before us don't want to try new things, i mean how good is google maps but most of the elderly generation prefer to get lost then use that wicked old technology. Although that is slowly starting to change and newer technology's and teachings are being embraced. Ok so what about the apprentice in japan who says his oyakata promotes pinching on junipers? I haven't had a full conversation with him about this yet but my guess is he is talking about removing the growing tip with a pinch rather then scissors and not actually performing pinching as a growth suppression technique.
Here are my thoughts ( and many others thoughts, including some top level professionals ) on pinching junipers. It should not be done, Ever. Now once again we are talking about the technique of pinching to supress the first flush of growth in spring, not the physical act of removing some growth by pinching it off the tree. The reason i say never do this is because with junipers all their energy is in their foliage, so imagine the tree has $100 worth of energy in last years growth, spring starts and it invests $50 worth of energy to eventually get back $100 worth of energy giving it $150 worth of energy moving forward. so basically it used some stored energy to put out more new growth to expand its photosynthetic surface which will allow it to create more sugars and energy then it could before which is a positive investment, especially because in summer it will likely shed its old growth.
Now lets just say spring starts, the tree has $100 worth of energy and invests $50 worth of energy to expand its photosynthetic capabilities. but as that new growth starts to emerge old pinchy fingers comes along and pinches off all the new growing tips the tree just invested in. Now the tree is down $50 worth of energy with no new growth to help return that investment. So the tree thinks well i cant spend another $50 otherwise ill be broke, so lets invest $25 and hope to see a return of $50 leaving me with $75 when all is said and done, the tree wont break even but wont be broke. Now lets just imagine that $25 worth of new growth starts to emerge and you pinch it again... If this cycle continues the tree will end up going broke ( die ), the best case scenario is the tree breaks even or just under each year (no progress, just keeping the tree alive but not vigorous. ) We know with junipers and a lot of other species in fact it is good practise to allow growth to flush, harden off, return energy to the tree then prune. That's why i mentioned earlier about the maples and pinching, its not a good idea to do it year after year because eventually you will hit $0. But to get that smaller growth we need to pinch ( among other things ), just as long as every now and then we allow the tree to be able to flush and re fill the account. But remember maples store energy in their trunks and roots, not in the foliage like junipers so pinching on junipers is always a no go zone.
Now before we finish i just want to clarify again we are talking about pinching as the technique of supressing new growth at the time of the first spring flush. I have an old Bonsai book in my library written by harry tomlinson that actually has a section on pinching junipers and the technique is taught in the book. This can cause a real grey area because in that book what he teaches is actually a decent technique. He starts by saying that the juniper he is pinching was allowed to grow for 2 months in spring before pinching the tree. the reason he is pinching the growth off is because most people rush with their scissors and cut through the juniper needles causing them to brown off and die back slightly. Pinching the growth off with your finger tips allows you to remove growth precisely without the risk of die back and browning off. what he is talking about is pruning as a physical technique with his fingers to avoid bad looking foliage if he rushes with his scissors. Most people confuse this with the pinching technique used on deciduous trees to supress growth to shorten internodes.
so if you ever have some one suggest to you to pinch your junipers try and clarify if they are just talking about using their fingers to prune rather then scissors or if they are talking about growth suppression in spring because one is ok and the other is not and unfortunaly they both share the same name, pinching.
I hope this has helped clear up another confusing subject in Bonsai.
Until Next Time, Enjoy Your Bonsai Journey.